#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>
#define pb push_back
#define fi first
#define se second
#define dd(x) cout<<#x<<" is "<<x<<endl;
const int N = 3005;
vector<pii>adj[N];
int dis[N];
int dis1[N];
const int inf = 1e16;
signed main(){
ios::sync_with_stdio(0); cin.tie(0);
int n,m; cin>>n>>m;
int s,t,l,k; cin>>s>>t>>l>>k;
for(int i=0; i<m; i++){
int a,b,c; cin>>a>>b>>c;
adj[a].pb({b,c});
adj[b].pb({a,c});
}
priority_queue<pii,vector<pii>,greater<pii>>pq;
for(int i=0; i<=n; i++) dis[i] = inf;
dis[s] = 0;
pq.push({0,s});
while(!pq.empty()){
auto[d,x] = pq.top(); pq.pop();
if(d!=dis[x]) continue;
for(auto [i,w]: adj[x]){
if(dis[i] == inf or dis[i] > d+w){
dis[i] = d+w;
pq.push({d+w,i});
}
}
}
//for(int i=1; i<=n; i++) cout<<dis[i]<<" ";
//cout<<endl;
priority_queue<pii,vector<pii>,greater<pii>>pq1;
for(int i=0; i<=n; i++) dis1[i] = inf;
dis1[t] = 0;
pq1.push({0,t});
while(!pq1.empty()){
auto[d,x] = pq1.top(); pq1.pop();
if(d!=dis1[x]) continue;
for(auto [i,w]: adj[x]){
if(dis1[i] == inf or dis1[i] > d+w){
dis1[i] = d+w;
pq1.push({d+w,i});
}
}
}
//dd(dis[t])
if(dis[t] <= k){
cout<<n*(n-1)/2;
//dd(1)
return 0;
}
int ans=0;
for(int i=1; i<=n; i++){
for(int j=1; j<=n; j++){
if(dis[i] + l + dis1[j] <= k) ans++;
}
}
cout<<ans;
return 0;
}
