#include <iostream>
#include <queue>
#include <vector>
using namespace std;
struct node {
    int idx;
    int shortest_path;
    node() {}
    node(int _idx, int _shortest_path) {
        idx = _idx;
        shortest_path = _shortest_path;
    }
    bool operator < (const node &tmp) const {
        return shortest_path > tmp.shortest_path;
    }
};
int main()
{
    int n, m; // number of nodes and edges 
    cin >> n >> m;
    
    vector<pair<int, int> > graph[n + 5];
    for(int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        graph[a].push_back(make_pair(b, c));
        graph[b].push_back(make_pair(a, c));
    }
    int S, E;
    cin >> S >> E;
    priority_queue<node> pq;
    pq.push(node(S, 0));
    vector<bool> visited(n, false);
    while(!pq.empty()) {
        node c = pq.top();
        pq.pop();
        visited[c.idx] = true;
        if(c.idx == E) {
            cout << c.shortest_path << endl;
            break;
        }
        for(int i = 0; i < graph[c.idx].size(); i++) {
            int sosed = graph[c.idx][i].first;
            int rebro = graph[c.idx][i].second;
            if(!visited[sosed]) {
                pq.push(node(sosed, rebro + c.shortest_path));
            }
            
        }
    }
    
    return 0;
}
/*
5 6
0 1 19
0 2 14
1 2 20
2 3 10
2 4 100
3 4 13


*/