#include<bits/stdc++.h> using namespace std; #define ll long long const ll nx = 2e5+5, inf = 4e18; ll n,m,s,t,l,k,cnt,pos[nx]; vector<pair<int,ll>> adj[nx]; vector<pair<ll,int>> possibleS, possibleT; vector<ll> dijkstra(int st) { vector<ll> dist(n+1,inf); priority_queue<pair<ll,int>, vector<pair<ll,int>>, greater<pair<ll,int>>> pq; dist[st] = 0; pq.push({0,st}); while(!pq.empty()) { auto [d, u] = pq.top(); pq.pop(); if(d > dist[u]) continue; for(auto [v,w] : adj[u]) { if(d+w < dist[v]) { dist[v] = d+w; pq.push({dist[v],v}); } } } return dist; } int main() { ios::sync_with_stdio(false); cin.tie(0); cin>>n>>m>>s>>t>>l>>k; for(int i = 1; i <= n; i++) pos[i] = inf; for(int i = 1; i <= m; i++) { int u,v; ll w; cin>>u>>v>>w; adj[u].push_back({v,w}); adj[v].push_back({u,w}); } vector<ll> distS = dijkstra(s); vector<ll> distT = dijkstra(t); if(distS[t] <= k) { cout<<n*(n-1)/2; return 0; } for(int i = 1; i <= n; i++) { if(distS[i]+l <= k) possibleS.push_back({distS[i]+l, i}); if(distT[i] <= k) possibleT.push_back({distT[i], i}); } sort(possibleT.begin(), possibleT.end()); if(possibleS.empty() || possibleT.empty()) return cout<<0, 0; for(int i = 0; i < possibleT.size(); i++) pos[possibleT[i].second] = i; for(int i = 0; i < possibleS.size(); i++) { ll cur = possibleS[i].first; int idx = possibleS[i].second; if(cur + possibleT[0].first > k) continue; int l = 0, r = possibleT.size()-1; while(l<r) { int md = (l+r+1)/2; if(cur+possibleT[md].first <= k) l = md; else r = md-1; } cnt += l + 1; } cout<<cnt; }