#include <iostream>
#include <deque>
#include <vector>
#include <climits>
#include <cstring>
using namespace std;
#define lim 1000
int w[lim][lim];
int bfs(vector<int> *v,int root,int key){
	deque<int> d;
	int dist[lim+1];
	memset(dist,lim*lim,sizeof(int)*(lim));
	dist[root]=0;
	d.push_front(root);
	while(not d.empty()){
		int node=d.front();
		d.pop_front();
		for(int i=0;i<v[node].size();i++){
			if(dist[node]+w[node][v[node][i]]<dist[v[node][i]]){
				dist[v[node][i]]=dist[node]+w[node][v[node][i]];
				if(w[node][v[node][i]]==1)d.push_back(v[node][i]);
				else d.push_front(v[node][i]);
			}
		}
	}
	return dist[key];
}
int main(){
	int n,m,s,d; // n vertices, m edges
	cin>>n>>m;
	vector<int> v[lim];
	for(int i=0;i<m;i++){
		int x,y,z;
		cin>>x>>y>>z;
		w[x][y]=w[y][x]=z;
		v[x].push_back(y);
		v[y].push_back(x);
	}
	cin>>s>>d;
	cout<<bfs(v,s,d)<<endl;
}