#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
int n, m;
cin >> n >> m;
int s, t, l;
ll k;
cin >> s >> t >> l >> k;
vector<vector<pair<int, int>>> adj(n + 1);
for (int i = 0; i < m; ++i) {
int a, b, w;
cin >> a >> b >> w;
adj[a].push_back({b, w});
adj[b].push_back({a, w});
}
auto dijikstra = [&](int st, vector<ll>& dist) -> void {
priority_queue<array<ll, 2>> pq;
pq.push({0, st});
dist[st] = 0;
while (pq.size()) {
ll d = -pq.top()[0];
int v = pq.top()[1];
pq.pop();
if (dist[v] != d) continue;
for (auto& [u, w] : adj[v]) {
if (dist[u] > dist[v] + w) {
dist[u] = dist[v] + w;
pq.push({-dist[u], u});
}
}
}
};
const ll INF = 1e18;
vector<ll> dist1(n + 1, INF), dist2(n + 1, INF);
dijikstra(s, dist1);
dijikstra(t, dist2);
int res = 0;
if (dist1[t] <= k) {
cout << n * (n - 1) / 2 << "\n";
return 0;
}
for (int i = 1; i <= n; ++i) {
for (int j = 1; j <= n; ++j) {
if (i == j) continue;
ll total = min(dist1[j], l + dist1[i]) + dist2[j];
//~ cout << i << " -> " << j << " = " << total << "\n";
if (total <= k) {
res += 1;
}
}
}
cout << res << "\n";
}
