#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;
struct node {
    int idx;
    int cost;
    
    node(){}
    node(int _idx, int _cost) {
        idx = _idx;
        cost = _cost;
    }
    bool operator < (const node &tmp) const {
        return cost > tmp.cost;
    }
};
int main() {
   
    int n, m;
    cin >> n >> m;
    vector<pair<int, int> > graph[n + 1];
    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 + 1, false);
    
    while(!pq.empty()) {
        node current_node = pq.top();
        pq.pop();
        visited[current_node.idx] = true;
        if(current_node.idx == E) {
            cout << current_node.cost << endl;
            break;
        }
        for(int i = 0; i < graph[current_node.idx].size(); i++) {
            int sosed = graph[current_node.idx][i].first;
            int rebro = graph[current_node.idx][i].second;
            if(!visited[sosed]) {
                pq.push(node(sosed, current_node.cost + rebro));
            }
        }
    }
    return 0;
}