#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long)1e18;
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, m, s, t, u, v;
cin >> n >> m >> s >> t >> u >> v;
vector<vector<pair<int, int>>> adj(n + 1);
while(m--){
int a, b, c;
cin >> a >> b >> c;
adj[a].emplace_back(b, c);
adj[b].emplace_back(a, c);
}
auto Do = [&](int src, vector<long long> &d)->void{
fill(d.begin(), d.end(), inf);
vector<bool> in_Q(n + 1);
d[src] = 0;
priority_queue<pair<long long, int>> pq;
pq.push({0, src});
while(!pq.empty()){
auto [_, node] = pq.top();
pq.pop();
if(in_Q[node]) continue;
in_Q[node] = 1;
for(auto [to, cost] : adj[node]){
if(d[node] + cost < d[to]){
d[to] = d[node] + cost;
pq.push({-d[to], to});
}
}
}
};
vector<long long> D1(n + 1);
Do(s, D1);
int cr = t;
bool unique = 1;
while(cr != s){ // making the edges in the SP free.
int cnt = 0;
for(auto &[node, cost] : adj[cr]){
if(D1[node] + cost == D1[cr]){
cost = 0;
for(auto &[node2, cost2] : adj[node]){
if(node2 == cr){
cost2 = 0;
}
}
cr = node;
++cnt;
unique &= (cnt == 1);
}
}
}
if(unique){
vector<long long> Du(n + 1);
Do(u, Du);
cout << Du[v] << '\n';
return 0;
}
return 0;
}
