#include <iostream>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;
const int maxn = 100005;
const int INF = 2e9;
struct node {
    int idx, 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;
    }
};
vector<pair<int, int>> graph[maxn];
int main(){
    int n, m;
    cin >> n >> m;
    
    
    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));
    }
    
    priority_queue<node> pq;
    
    int S, E;
    cin >> S >> E;
    
    pq.push(node(S, 0));
    
    vector<bool> visited(n, false);
    vector<int> dist(n, INF);
    
    dist[S] = 0;
    
    while(!pq.empty()) {
        node c = pq.top();
        pq.pop();
        
        if(visited[c.idx]) {
            continue;
        }
        
        visited[c.idx] = true;
        
        for(int i = 0; i < (int) graph[c.idx].size(); i++) {
            int neighbour = graph[c.idx][i].first;
            int weight = graph[c.idx][i].second;
            
            if(!visited[neighbour] and c.shortest_path + weight < dist[neighbour]) {
                dist[neighbour] = c.shortest_path + weight;
                pq.push(node(neighbour, dist[neighbour]));
            }
            
        }
    }
   
    cout << dist[E] << endl;
    
    
    
    return 0;
}