#include <bits/stdc++.h>
#define int long long
#define ll long long
#define pb push_back
#define fi first
#define se second
#define lf (id<<1)
#define rg ((id<<1)|1)
#define md ((l+r)>>1)
#define ld long double
using namespace std;
typedef pair<int,int> pii;
typedef pair<char,char> pcc;
typedef pair<int,pii> ipii;
typedef pair<pii,pii> ipiii;
const int MAXN = 3e5+50;
const int SQRT = 610;
const int MAXA = 50;
const int MOD = 998244353;
const int LOG = 21;
const int INF = 1e18;
const ld EPS = 1e-12;
int n, m, s, t, l, k;
vector <pii> adj[MAXN];
priority_queue <pii, vector<pii>, greater<pii>> pq;
int dis[MAXN], dis2[MAXN];
void dji2(){
for(int i=1; i<=n; i++) dis2[i] = INF;
dis2[t] = 0; pq.push({0, t});
while(!pq.empty()){
int nw = pq.top().se, dist = pq.top().fi; pq.pop();
if(dist > dis2[nw]) continue;
for(auto [nx, ed] : adj[nw]){
if(dis2[nx] > dist+ed){
dis2[nx] = dist+ed; pq.push({dis2[nx], nx});
}
}
}
}
void dji(){
for(int i=1; i<=n; i++) dis[i] = INF;
dis[s] = 0; pq.push({0, s});
while(!pq.empty()){
int nw = pq.top().se, dist = pq.top().fi; pq.pop();
if(dist > dis[nw]) continue;
for(auto [nx, ed] : adj[nw]){
if(dis[nx] > dist+ed){
dis[nx] = dist+ed; pq.push({dis[nx], nx});
}
}
}
}
signed main(){
// ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin>>n>>m;
cin>>s>>t>>k>>l;
for(int i=1; i<=m; i++){
int x, y, z; cin>>x>>y>>z;
adj[x].pb({y,z}); adj[y].pb({x,z});
}
dji(); dji2();
// for(int i=1; i<=n; i++){
// cout << i << ' ' <<dis[i]<<' '<<dis2[i]<< "pp\n";
// }
int ans = 0;
if(dis[t] > l){
for(int i=1; i<=n; i++){
for(int j=i+1; j<=n; j++){
if(min(dis[i]+dis2[j], dis2[i]+dis[j])+k <= l) ans++;
}
}
} else ans = n*(n-1)/2;
cout << ans << '\n';
}
