#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
#include<vector>
#include<queue>
#include<limits>
template<typename T>
vector<T>dijkstra(int s,const vector<vector<pair<int,T> > >&G,T INF=numeric_limits<T>::max())
{
	int n=G.size();
	vector<T>d(n,INF);
	vector<int>parent(n,-1);
	priority_queue<pair<T,int>,vector<pair<T,int> >,greater<pair<T,int> > >P;
	d[s]=0;
	P.push(make_pair(d[s],s));
	while(!P.empty())
	{
		pair<T,int>p=P.top();P.pop();
		int v=p.second;
		if(d[v]<p.first)continue;
		for(const pair<int,T>&e:G[v])
		{
			int u=e.first;
			T cost=d[v]+e.second;
			if(d[u]>cost)
			{
				d[u]=cost;
				parent[u]=v;
				P.push(make_pair(d[u],u));
			}
		}
	}
	return d;
}
int N,M,P,Q,T;
main()
{
	cin>>N>>M>>P>>Q>>T;
	vector<vector<pair<int,long> > >G(N);
	for(int i=0;i<M;i++)
	{
		int a,b,c;cin>>a>>b>>c;
		a--,b--;
		G[a].push_back(make_pair(b,c));
		G[b].push_back(make_pair(a,c));
	}
	P--,Q--;
	vector<long>d1=dijkstra(0,G);
	vector<long>dp=dijkstra(P,G);
	vector<long>dq=dijkstra(Q,G);
	long ans=-1;
	if(d1[P]+dp[Q]+dq[0]<=T)ans=T;
	for(int i=0;i<N;i++)for(int j=0;j<N;j++)
	{
		if(d1[i]+max(dp[i]+dp[j],dq[i]+dq[j])+d1[j]<=T)
		{
			ans=max(ans,T-max(dp[i]+dp[j],dq[i]+dq[j]));
		}
	}
	cout<<ans<<endl;
}