// joi final round 2024
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define vi vector<long long>
#define all(x) x.begin(), x.end()
#define endl "\n"
#define pr pair<ll, ll>
#define ff first
#define ss second
void solution();
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
solution();
return 0;
}
const int N = 2e5+10;
vector<pr> adj[N];
ll n, m;
void dij(int a, vi &dist) {
dist.resize(n+1, 2e15);
dist[0] = 0;
vector<bool> vis(n+1);
priority_queue<pr> q;
dist[a] = 0;
q.push({0, a});
while (!q.empty()) {
auto [d, u] = q.top(); q.pop();
if (vis[u]) continue;
vis[u] = true;
for (auto [v, w] : adj[u]) {
if (dist[u] + w < dist[v]) {
dist[v] = dist[u] + w;
q.push({-dist[v], v});
}
}
}
}
void solution() {
cin >> n >> m;
ll S, T, l, k;
cin >> S >> T >> l >> k;
while (m--) {
ll a, b, w;
cin >> a >> b >> w;
adj[a].push_back({b, w});
adj[b].push_back({a, w});
}
vi d1, d2;
dij(S, d1);
dij(T, d2);
if (d1[T] <= k) {
cout << n*(n-1)/2 << endl;
return;
}
ll ans = 0;
sort(all(d1));
sort(all(d2));
int j = n;
for (int i = 1; i <= n; i++) {
while (j >= 1 && d2[j] > k-l-d1[i]) j--;
ans += j;
}
// j = n;
// for (int i = 1; i <= n; i++) {
// while (j >= 1 && d1[j] > k-l-d2[i]) j--;
// ans+=j;
// }
cout << ans << endl;
}
