#include<bits/stdc++.h>
using namespace std;

#define all(v) v.begin(),v.end()
using ll = long long;
using ull = unsigned long long;
using vll=vector<ll>;
const ll INF=1ll<<60;
using vp=vector<pair<ll, ll>>;
using P = pair<ll,ll>;
using vvll = vector<vector<P>>;


ll N,M,p,Q,T;

vll dik(ll s,vvll &ab){
    vll dist(N,INF);
    priority_queue<P,vector<P>,greater<P>>q;
    dist[s]=0;
    q.push({0,s});
    while(!q.empty()){
        auto x=q.top();q.pop();
        if(dist[x.second]<x.first)continue;
        for(auto to:ab[x.second]){
            if(dist[to.second]<=to.first+x.first)continue;
            dist[to.second]=to.first+x.first;
            q.push({dist[to.second],to.second});
        }
    }
    return dist;
}

int main(){
    cin>>N>>M>>p>>Q>>T;
    p--;Q--;
    vvll ab(N);
    for(int i=0;i<M;i++){
        ll a,b,c;
        cin>>a>>b>>c;
        a--;b--;
        ab[a].push_back({c,b});
        ab[b].push_back({c,a});
    }
    vll dist=dik(0,ab);
    vll distp=dik(p,ab);
    vll distq=dik(Q,ab);
    ll ans=-1;
    if(dist[p]+distp[Q]+dist[Q]<=T)ans=max(ans,T);
    for(int i=0;i<N;i++){
        for(int j=0;j<N;j++){
            if(max(distp[i]+distp[j],distq[i]+distq[j])+dist[i]+dist[j]<=T)ans=max(ans,T-(max(distp[i]+distp[j],distq[i]+distq[j])));
        }
    }
    cout << ans << endl;
}