#include 
#include 
#include 
#include 
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 > 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 pq;
    pq.push(node(S, 0));
    vector visited(n + 1, false);
    vector distance(n + 1, 2e9);
    
    distance[S] = 0; // start
    
    while(!pq.empty()) {
        node current_node = pq.top();
        pq.pop();
        visited[current_node.idx] = true;
        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] and current_node.cost + rebro < distance[sosed]) {
                pq.push(node(sosed, current_node.cost + rebro));
                distance[sosed] = current_node.cost + rebro;
            }
        }
    }
    cout << distance[E] << endl; // end
    return 0;
}