// subtask 2
#include "bits/stdc++.h"
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) (int)(x).size()
using namespace std;
using ll = long long;
using pii = pair<int, int>;
const char nl = '\n';
const ll LINF = 0x3f3f3f3f3f3f3f3f;
const int INF = 0x3f3f3f3f;
int main() {
ios::sync_with_stdio(0), cin.tie(0);
int n, m; cin >> n >> m;
int a, b; cin >> a >> b;
int ini, fim; cin >> ini >> fim;
using pll = pair<ll, ll>;
vector<vector<pll>> adj(n + 1);
for (int i = 0; i < m; i++) {
int a, b; ll c; cin >> a >> b >> c;
adj[a].push_back({b, c});
adj[b].push_back({a, c});
}
vector<ll> dist(n + 1);
vector<int> pai(n + 1);
set<pii> zero;
auto dijkstra = [&](int s) -> void {
fill(all(dist), LINF);
fill(all(pai), 0);
priority_queue<pll, vector<pll>, greater<pll>> pq;
pq.push({0, s}); dist[s] = 0;
while (!pq.empty()) {
auto [d, x] = pq.top(); pq.pop();
if (dist[x] != d) continue;
for (auto [k, dd] : adj[x]) {
if (zero.count({x, k})) dd = 0;
if (d + dd < dist[k]) {
dist[k] = d + dd;
pai[k] = x;
pq.push({dist[k], k});
}
}
}
};
dijkstra(a);
vector<int> v = {b};
while (v.back() != a)
v.push_back(pai[v.back()]);
reverse(all(v));
for (int i = 0; i < sz(v) - 1; i++) {
zero.insert({v[i], v[i + 1]});
zero.insert({v[i + 1], v[i]});
}
dijkstra(ini);
cout << dist[fim] << nl;
return 0;
}
