#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int const maxn = 1e5+1;
vector<vector<array<ll,2> > > adj(maxn);
ll n;
ll odS[maxn];
bool visited[maxn];
void djikstra(ll pocetok,ll kraj)
{
priority_queue<array<ll,2>,vector<array<ll,2> > , greater<array<ll,2> > > pq;
memset(visited,0,sizeof(visited));
pq.push({0,pocetok});
while (pq.size())
{
ll p = pq.top()[1],d = pq.top()[0];pq.pop();
if (visited[p]) continue;
visited[p] = true;
odS[p] = d;
if (p == kraj) continue;
for (auto a: adj[p])
{
if (visited[a[0]] == false) pq.push({d + a[1],a[0]});
}
}
}
bool pripagja[maxn];
void dfs(ll p,ll const kraj)
{
pripagja[p] = true;
if (p == kraj) return;
for (auto s: adj[p])
{
if (odS[s[0]] + s[1] == odS[p] && pripagja[s[0]] == false) dfs(s[0],kraj);
}
}
ll f(ll pocetok,ll kraj)
{
priority_queue<array<ll,2>,vector<array<ll,2> > , greater<array<ll,2> > > pq;
pq.push({0,pocetok});
memset(visited,0,sizeof(visited));
while(pq.size())
{
ll p = pq.top()[1],d = pq.top()[0];pq.pop();
if (p == kraj) return d;
if (visited[p]) continue;
visited[p] = true;
for (auto a: adj[p])
{
if (visited[a[0]] == false)
{
if (pripagja[p] && pripagja[a[0]]) pq.push({d,a[0]});
else pq.push({d + a[1],a[0]});
}
}
}
}
int main()
{
ll m,s,t,pocetok,kraj;
cin>>n>>m>>s>>t>>pocetok>>kraj;
for (ll i=0;i<m;i++)
{
ll a,b,c;
cin>>a>>b>>c;
adj[a].push_back({b,c});
adj[b].push_back({a,c});
}
djikstra(t,s);
dfs(s,t);
//for (ll i=1;i<=n;i++) cout<<odS[i]<<" "<<pripagja[i]<<endl;
cout<<f(pocetok,kraj);
return 0;
}
