#include<bits/stdc++.h>

using namespace std;

#define N 505

vector<pair<int,int>> adj[N];

int n,m,A,B,done[N],apcacity;// 容量

int main(){

    ios::sync_with_stdio(0);

    cin.tie(0);

    cin>>n>>m;

    for(int i=0,u,v,w;i<m;i++){

        cin>>u>>v>>w;

        adj[u].push_back({v,w});

        adj[v].push_back({u,w});

    }

    cin>>A>>B;

    priority_queue<pair<int,int>> pq;

    pq.push({0,A});

    while(!pq.empty()){

        auto e=pq.top();pq.pop();

        int w=e.first,v=e.second;

        if(done[v]!=0) continue;

        done[v]=w;

        apcacity=min(apcacity,w);

        if(v==B) break;

        for(auto k:adj[v]){

            if(done[k.first]!=0) continue;// 不一定要

            pq.push({-k.second,k.first});

        }

    }

    if(done[B]==0) cout<<"-1";

    else cout<<-apcacity;

}