#include <iostream>
#include <queue>
#include <vector>
#include <map>
#define infi 0x7fffffff
using namespace std;

typedef pair<int,int> arco;

//priority_queue< int, vector<int>, greater<int> > pq1;

int min_camino(vector< vector<arco> > G, int x, int y){
	vector<bool> b(G.size(),false);
	vector<int>  p(G.size(),infi);
	priority_queue< arco, vector<arco>, greater<arco> > Q;
    p[x] = 0;
	Q.push( arco(0,x) );
    while (not Q.empty()){
        int vertex = Q.top().second;
        Q.pop();
        if (not b[vertex]){
            b[vertex] = true;
            int tam = G[vertex].size();
            for (int i = 0; i < tam; ++i){
                int adyacente = G[vertex][i].second;
                int peso = G[vertex][i].first;
                if( (p[vertex]+peso) < p[adyacente] ){
					p[adyacente] = p[vertex]+peso;
					Q.push(arco(p[adyacente],adyacente));
				}
            }
        }
    }
    return p[y];
}

int main() {
	int n,m,u,v,w,x,y;
	while(cin >> n >> m){
		vector< vector<arco> > G(n,vector<arco>() );
		for(int i=0;i<m;++i){
			cin >> u >> v >> w;
			G[u].push_back( arco(w,v) ); //PRIMER VALOR: PESO || SEGUNDO VALOR: VERTICE ADYACENTE
		}
        cin >> x >> y;
		int r = min_camino(G,x,y);
		if( r!= infi )
			cout << r << endl;
		else
			cout << "no path from " << x << " to " << y << endl;
	}
}