#include <iostream> #include <bits/stdc++.h> #define ll long long using namespace std; const ll maxn = 2*1e5+5, INF = 4e18+9; vector<ll> dijkstra(int n, int s, vector<vector<pair<ll, ll>>> &adj){ vector<ll> dist(n+1, INF); dist[s] = 0; vector<bool> vis(n+1, false); priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> pq; pq.push({0, s}); while(!pq.empty()){ ll d_u = pq.top().first; int u = pq.top().second; pq.pop(); if(vis[u]){ continue; } vis[u] = true; for(auto it : adj[u]){ int v = it.first; ll w = it.second; if(vis[v]) continue; if(dist[v] > d_u+w){ dist[v] = d_u+w; pq.push({dist[v], v}); } } } return dist; } void solve(){ int n, m; cin >> n >> m; ll S, T, L, K; cin >> S >> T >> L >> K; vector<vector<pair<ll, ll>>> adj(n+1); for(int i = 1; i <= m; i++){ int u, v, w; cin >> u >> v >> w; adj[u].push_back({v, w}); adj[v].push_back({u, w}); } vector<ll> dS = dijkstra(n, S, adj), dT = dijkstra(n, T, adj); if(dS[T] <= K){ cout << (ll)n*(n-1)/2; return; } vector<ll> tv; for(int i = 1; i <= n; i++){ tv.push_back(dT[i]); } sort(tv.begin(), tv.end()); tv.push_back(INF); K -= L; ll ans = 0; for(int i = 1; i <= n; i++){ int p = upper_bound(tv.begin(), tv.end(), K-dS[i]) - tv.begin() - 1; p++; ans += p; } cout << ans; } int main(){ ios_base::sync_with_stdio(false); cin.tie(NULL); solve(); }