#include 
#include 
#include 
#include 
#include 
using namespace std;


struct node {
    int idx;
    int distance;
    
    node() {}
    node(int _idx, int _distance) {
        idx = _idx;
        distance = _distance;
    }
    
    bool operator < (const node &tmp) const {
        return distance > tmp.distance;
    }
    
};
int main() {
    int n; // broj na teminja
    int m; // brojot na rebra
    cin >> n >> m;
    
    vector > graph[n + 1];
    for(int i = 0; i < m; i++) {
        int a, b, c; // povrzani se teminjata a i b so distanca c
        cin >> a >> b >> c;
        graph[a].push_back(make_pair(b, c));
        graph[b].push_back(make_pair(a, c));
    }
    
    int S, E;
    // S --> pocetno teme
    // E --> krajno teme
    cin >> S >> E;
    
    priority_queue pq;
    pq.push(node(S, 0)); // prviot element vo priority queue
    
    bool visited[n + 1];
    for(int i = 0; i < n; i++) {
        visited[i] = false;
    }
    
    while(!pq.empty()) {
        node c = pq.top();
        pq.pop();
        
        visited[c.idx] = true;
        if(c.idx == E) {
            cout << c.distance << 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, c.distance + rebro));
            }
        }
    }
    
    return 0;
}