Графови

import java.util.Iterator;
import java.util.LinkedList;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.NoSuchElementException;

interface Stack<E> {

    // Elementi na stekot se objekti od proizvolen tip.

    // Metodi za pristap:

    public boolean isEmpty ();
        // Vrakja true ako i samo ako stekot e prazen.

    public E peek ();
        // Go vrakja elementot na vrvot od stekot.

    // Metodi za transformacija:

    public void clear ();
        // Go prazni stekot.

    public void push (E x);
        // Go dodava x na vrvot na stekot.

    public E pop ();
        // Go otstranuva i vrakja elementot shto e na vrvot na stekot.
}

class ArrayStack<E> implements Stack<E> {
    private E[] elems;
    private int depth;

    @SuppressWarnings("unchecked")
    public ArrayStack (int maxDepth) {
        // Konstrukcija na nov, prazen stek.
        elems = (E[]) new Object[maxDepth];
        depth = 0;
    }


    public boolean isEmpty () {
        // Vrakja true ako i samo ako stekot e prazen.
        return (depth == 0);
    }


    public E peek () {
        // Go vrakja elementot na vrvot od stekot.
        if (depth == 0)
            throw new NoSuchElementException();
        return elems[depth-1];
    }


    public void clear () {
        // Go prazni stekot.
        for (int i = 0; i < depth; i++)  elems[i] = null;
        depth = 0;
    }


    public void push (E x) {
        // Go dodava x na vrvot na stekot.
        elems[depth++] = x;
    }


    public E pop () {
        // Go otstranuva i vrakja elementot shto e na vrvot na stekot.
        if (depth == 0)
            throw new NoSuchElementException();
        E topmost = elems[--depth];
        elems[depth] = null;
        return topmost;
    }
}


class Edge{
    private int fromVertex, toVertex;
    private float weight;
    public Edge(int from, int to, float weight){
        this.fromVertex = from;
        this.toVertex = to;
        this.weight = weight;
    }

    public int getFrom(){
        return this.fromVertex;
    }
    public int getTo(){
        return this.toVertex;
    }
    public float getWeight(){
        return this.weight;
    }
}

class GraphNodeNeighbor<E> {
    GraphNode<E> node;
    float weight;

    public GraphNodeNeighbor(GraphNode<E> node, float weight) {
        this.node = node;
        this.weight = weight;
    }

    public GraphNodeNeighbor(GraphNode<E> node) {
        this.node = node;
        this.weight = 0;
    }

    @Override
    public boolean equals(Object obj) {
        @SuppressWarnings("unchecked")
        GraphNodeNeighbor<E> pom = (GraphNodeNeighbor<E>)obj;
        return pom.node.equals(this.node);
    }
}

class GraphNode<E> {
    private int index; //index (reden broj) na temeto vo grafot
    private E info;
    private LinkedList<GraphNodeNeighbor<E>> neighbors;

    public GraphNode(int index, E info) {
        this.index = index;
        this.info = info;
        neighbors = new LinkedList<GraphNodeNeighbor<E>>();
    }

    public boolean containsNeighbor(GraphNode<E> o){
        GraphNodeNeighbor<E> pom = new GraphNodeNeighbor<E>(o,0);
        return neighbors.contains(pom);
    }

    public void addNeighbor(GraphNode<E> o, float weight){
        GraphNodeNeighbor<E> pom = new GraphNodeNeighbor<E>(o,weight);
        neighbors.add(pom);
    }

    public void removeNeighbor(GraphNode<E> o){
        GraphNodeNeighbor<E> pom = new GraphNodeNeighbor<E>(o,0);
        if(neighbors.contains(pom))
            neighbors.remove(pom);
    }

    @Override
    public String toString() {
        String ret= "INFO:"+info+" SOSEDI:";
        for(int i=0;i<neighbors.size();i++)
        ret+="("+neighbors.get(i).node.info+","+neighbors.get(i).weight+") ";
        return ret;

    }

    public void updateNeighborWeight(GraphNode<E> o, float weight){
        Iterator<GraphNodeNeighbor<E>> i = neighbors.iterator();
        while(i.hasNext()){
            GraphNodeNeighbor<E> pom = i.next();
            if(pom.node.equals(o))
                pom.weight = weight;
        }

    }

    @Override
    public boolean equals(Object obj) {
        @SuppressWarnings("unchecked")
        GraphNode<E> pom = (GraphNode<E>)obj;
        return (pom.info.equals(this.info));
    }

    public int getIndex() {
        return index;
    }

    public void setIndex(int index) {
        this.index = index;
    }

    public E getInfo() {
        return info;
    }

    public void setInfo(E info) {
        this.info = info;
    }

    public LinkedList<GraphNodeNeighbor<E>> getNeighbors() {
        return neighbors;
    }

    public void setNeighbors(LinkedList<GraphNodeNeighbor<E>> neighbors) {
        this.neighbors = neighbors;
    }

}

class Graph<E> {

    int num_nodes;
    GraphNode<E> adjList[];

    @SuppressWarnings("unchecked")
    public Graph(int num_nodes, E[] list) {
        this.num_nodes = num_nodes;
        adjList = (GraphNode<E>[]) new GraphNode[num_nodes];
        for (int i = 0; i < num_nodes; i++)
            adjList[i] = new GraphNode<E>(i, list[i]);
    }

    @SuppressWarnings("unchecked")
    public Graph(int num_nodes) {
        this.num_nodes = num_nodes;
        adjList = (GraphNode<E>[]) new GraphNode[num_nodes];
        for (int i = 0; i < num_nodes; i++)
            adjList[i] = new GraphNode<E>(i, null);
    }

    int adjacent(int x, int y) {
        // proveruva dali ima vrska od jazelot so
        // indeks x do jazelot so indeks y
        return (adjList[x].containsNeighbor(adjList[y])) ? 1 : 0;
    }

    void addEdge(int x, int y, float tezina) {
        // dodava vrska od jazelot so indeks x do jazelot so indeks y so tezina
        if (adjList[x].containsNeighbor(adjList[y])) {
            adjList[x].updateNeighborWeight(adjList[y], tezina);
        } else
            adjList[x].addNeighbor(adjList[y], tezina);
    }

    void deleteEdge(int x, int y) {
        adjList[x].removeNeighbor(adjList[y]);
    }

    // Funkcija za prebaruvanje na index na jazel so dadeno info vo listata na sosednost vo grafot
    int searchIndex(String key)
    {
        for(int i=0;i<num_nodes;i++){
            Iterator<GraphNodeNeighbor<E>> it = adjList[i].getNeighbors().iterator();
            while (it.hasNext()) {
                GraphNodeNeighbor<E> pom = it.next();
                if(pom.node.getInfo().equals(key))
                    return pom.node.getIndex();

            }
       }
       return -1;
    }


    float min_path(int from, int to)
    {

        float[] odDo = dijkstra(from,to);
        System.out.println();
        float[] doOd = dijkstra(to,from);
        System.out.println();

        return odDo[to] + doOd[from];
    }

    float[] dijkstra(int from, int to) {

        int prv = from;
        /* Minimalna cena do sekoe od teminjata */
        float distance[] = new float[this.num_nodes];
        /* dali za temeto e najdena konecnata (minimalna) cena */
        int previous[] = new int[this.num_nodes];
        boolean finalno[] = new boolean[this.num_nodes];
        for (int i = 0; i < this.num_nodes; i++) {
            distance[i] = -1;
            finalno[i] = false;
            previous[i] = Integer.MIN_VALUE;
        }

        finalno[from] = true;
        distance[from] = 0;

        /*
         * vo sekoj cekor za edno teme se dobiva konecna minimalna cena
         */
        for (int i = 1; i < this.num_nodes; i++) {
            /* za site sledbenici na from presmetaj ja cenata */
            Iterator<GraphNodeNeighbor<E>> it = adjList[from].getNeighbors().iterator();
            while (it.hasNext()) {
                GraphNodeNeighbor<E> pom = it.next();
                /* ako grankata kon sosedot nema konecna cena */
                if (!finalno[pom.node.getIndex()]) {
                    /* ako ne e presmetana cena za temeto */
                    if (distance[pom.node.getIndex()] <= 0) {
                        distance[pom.node.getIndex()] = distance[from]
                                + pom.weight;
                        previous[pom.node.getIndex()] = from;
                    }
                    /* inaku, ako e pronajdena poniska */
                    else if (distance[from] + pom.weight < distance[pom.node
                            .getIndex()]) {
                        distance[pom.node.getIndex()] = distance[from]
                                + pom.weight;
                        previous[pom.node.getIndex()] = from;

                    }
                }
            }

            /* najdi teme so min. cena koja ne e konecna */
            boolean minit = false; /* min. ne e inicijaliziran */
            int k = -1;
            float minc = -1;
            /* proveri gi site teminja */
            for (int j = 0; j < this.num_nodes; j++) {
                if (!finalno[j]&&distance[j] != -1) { /*ako cenata ne e  konecna*/
                    if (!minit) { /* ako ne e inicijaliziran minimumot */
                        minc = distance[k = j]; /* proglasi go ova e minimum */
                        minit = true; /* oznaci deka min e inicijaliziran */
                    }
                    /* proveri dali e pronajdeno teme so pomala cena */
                    else if (minc > distance[j]&&distance[j] > 0)
                        minc = distance[k = j];
                }
            }

            finalno[from = k] = true;
        }
        ArrayStack<E> S = new ArrayStack<>(1000);
        int u = to;
        while (previous[u] != Integer.MIN_VALUE) {
            S.push(adjList[u].getInfo());
            u = previous[u];

        }


        System.out.print(adjList[prv].getInfo() + " ");
        while (!S.isEmpty()) {
            System.out.print(S.pop() + " ");
        }


        return distance;

    }

    ArrayStack<E> dijkstra2(int from, int to) {

        /* Minimalna cena do sekoe od teminjata */
        float distance[] = new float[this.num_nodes];
        /* dali za temeto e najdena konecnata (minimalna) cena */
        boolean finalno[] = new boolean[this.num_nodes];
        int previous[] = new int[this.num_nodes];
        ArrayStack<E> S = new ArrayStack<>(this.num_nodes);
        for (int i = 0; i < this.num_nodes; i++) {
            distance[i] = -1;
            finalno[i] = false;
            previous[i] = Integer.MIN_VALUE;
        }

        finalno[from] = true;
        distance[from] = 0;

        /*
         * vo sekoj cekor za edno teme se dobiva konecna minimalna cena
         */
        for (int i = 1; i < this.num_nodes; i++) {

            /* za site sledbenici na from presmetaj ja cenata */
            Iterator<GraphNodeNeighbor<E>> it = adjList[from].getNeighbors().iterator();
            while (it.hasNext()) {
                GraphNodeNeighbor<E> pom = it.next();



                /* ako grankata kon sosedot nema konecna cena */
                if (!finalno[pom.node.getIndex()]) {
                    /* ako ne e presmetana cena za temeto */
                    if (distance[pom.node.getIndex()] <= 0) {
                        distance[pom.node.getIndex()] = distance[from]
                                + pom.weight;
                        previous[pom.node.getIndex()] = from;
                    }
                    /* inaku, ako e pronajdena poniska */
                    else if (distance[from] + pom.weight < distance[pom.node
                            .getIndex()]) {
                        distance[pom.node.getIndex()] = distance[from]
                                + pom.weight;
                        previous[pom.node.getIndex()] = from;

                    }
                }
            }

            /* najdi teme so min. cena koja ne e konecna */
            boolean minit = false; /* min. ne e inicijaliziran */
            int k = -1;
            float minc = -1;
            /* proveri gi site teminja */
            for (int j = 0; j < this.num_nodes; j++) {
                if (!finalno[j]&&distance[j] != -1) { /*ako cenata ne e  konecna*/
                    if (!minit) { /* ako ne e inicijaliziran minimumot */
                        minc = distance[k = j]; /* proglasi go ova e minimum */
                        minit = true; /* oznaci deka min e inicijaliziran */
                    }
                    /* proveri dali e pronajdeno teme so pomala cena */
                    else if (minc > distance[j]&&distance[j] > 0)
                        minc = distance[k = j];
                }
            }

            finalno[from = k] = true;
        }


        return  S;

    }




    @Override
    public String toString() {
        String ret = new String();
        for (int i = 0; i < this.num_nodes; i++)
            ret += adjList[i] + "\n";
        return ret;
    }

}

public class Cities {

    public static void main(String[] args) throws Exception{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        int n_nodes = Integer.parseInt(br.readLine());

        String grad[] = new String[n_nodes];
        Graph<String> g = new Graph<String>(n_nodes,grad);

        int n_edges = Integer.parseInt(br.readLine());

        int x,y; float tezina;
        String xInfo, yInfo, pom[];
        for(int i=0;i<n_edges;i++)
        {
            pom = br.readLine().split(" ");
            x = Integer.parseInt(pom[0]);
            xInfo = pom[1];
            y = Integer.parseInt(pom[2]);
            yInfo = pom[3];
            g.adjList[x].setInfo(xInfo);
            g.adjList[y].setInfo(yInfo);
            tezina = Float.parseFloat(pom[4]);
            g.addEdge(x,y,tezina);
        }

        String start = br.readLine();
        String end = br.readLine();
        br.close();

        int from = g.searchIndex(start);
        int to = g.searchIndex(end);

        float min_p = g.min_path(from,to);
        System.out.println(min_p);
    }

}