#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ff first
#define ss second
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define ertunt return
const int MOD = 998244353;
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
int main() {
ll n, m;
cin >> n >> m;
ll s, t, l, k;
cin >> s >> t >> l >> k;
vector<vector<pair<ll, ll>>> v(n + 1);
for (ll i = 0; i < m; i++) {
ll a, b, w;
cin >> a >> b >> w;
v[a].pb({b, w});
v[b].pb({a, w});
}
vector<ll> distt(n + 1, 1e14), dists(n + 1, 1e14);
dists[s] = 0;
distt[t] = 0;
set<pair<ll, ll>> pq;
pq.insert({0, s});
while (!pq.empty()) {
auto p = *pq.begin();
pq.erase(pq.begin());
for (auto [x, y] : v[p.ss]) {
if (dists[x] > dists[p.ss] + y) {
pq.erase({dists[x], x});
dists[x] = dists[p.ss] + y;
pq.insert({dists[x], x});
}
}
}
pq.insert({0, t});
while (!pq.empty()) {
auto p = *pq.begin();
pq.erase(pq.begin());
for (auto [x, y] : v[p.ss]) {
if (distt[x] > distt[p.ss] + y) {
pq.erase({distt[x], x});
distt[x] = distt[p.ss] + y;
pq.insert({distt[x], x});
}
}
}
if (distt[s] <= k) {
cout << n * (n - 1) / 2;
ertunt 0;
}
ll ans = 0;
for (ll i = 1; i <= n; i++) {
for (ll j = i + 1; j <= n; j++) {
if (dists[i] + l + distt[j] <= k or distt[i] + l + dists[j] <= k) ans++;
}
}
cout << ans << '\n';
}
