//import java.util.Iterator;
import java.util.Stack;
import java.util.LinkedList;
import java.util.Scanner;

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

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

    boolean containsNeighbor(GraphNode<E> o){
        return neighbors.contains(o);
    }

    void addNeighbor(GraphNode<E> o){
        neighbors.add(o);
    }

    void removeNeighbor(GraphNode<E> o){
        if(neighbors.contains(o))
            neighbors.remove(o);
    }

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

    }

    @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<GraphNode<E>> getNeighbors() {
        return neighbors;
    }

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


class Graph<E> {

    int num_nodes;
    GraphNode<E> adjList[];
    boolean visited[];

    @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];
    }

    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) {
        // dodava vrska od jazelot so indeks x do jazelot so indeks y
        if (!adjList[x].containsNeighbor(adjList[y])) {
            adjList[x].addNeighbor(adjList[y]);
        }
    }

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

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

    public int getID(String s)
    {
        for(int i = 0 ; i < num_nodes ; ++i)
            if(adjList[i].getInfo().equals(s))
                return i;
        return 0;
    }

    private void dfs(int n)
    {
        //System.out.println(adjList[n].getInfo() + " IS VISITED");
        visited[n] = true;
        LinkedList<GraphNode<E>> ns = adjList[n].getNeighbors();
        for(GraphNode<E> node : ns)
            if(!visited[node.getIndex()])
                dfs(node.getIndex());
    }

    public String solve(String start)
    {
        //System.out.println("STARTING WITH " + start);
        visited = new boolean[num_nodes];
        dfs(getID(start));
        for(int i = 0 ; i < num_nodes ; ++i)
            if(!visited[i])
            {
                //System.out.println("Not visited is " + adjList[i].getInfo());
                boolean flag = true;
                LinkedList<GraphNode<E>> ns = adjList[i].getNeighbors();
                for(GraphNode<E> node : ns)
                    if(!visited[node.getIndex()])
                        flag = false;
                if(flag)
                    return adjList[i].getInfo().toString();
            }
        return null;
    }

}

public class IzborPredmet {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        int N = in.nextInt();

        Graph<String> graph = new Graph<String>(N);

        for(int i = 0 ; i < N ; ++i)
            graph.adjList[i] = new GraphNode<String>(i, in.next());

        int M = in.nextInt();
        in.nextLine();

        for(int i = 0 ; i < M ; ++i)
        {
            String[] input = in.nextLine().split(" ");
            //System.out.println("Line " + i + " Starting with " + input[0]);
            int toAdd = graph.getID(input[0]);

            for(int j = 1 ; j < input.length ; ++j)
                graph.addEdge(toAdd, graph.getID(input[j]));
        }

        System.out.println(graph.solve(in.nextLine()));

        in.close();
    }
}