#define _USE_MATH_DEFINES
#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <complex>
#include <string>
#include <vector>
#include <array>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
#include <iterator>
#include <memory>
#include <regex>
using namespace std;

template <class T>
class EdgeBase
{
public:
    int to;
    T cost;
    EdgeBase(){};
    EdgeBase(int to0, T cost0){to = to0; cost = cost0;}
};
typedef EdgeBase<long long> Edge;

template<class T>
void shortestPath(const vector<vector<EdgeBase<T> > >& edges, int start, vector<T>& dist)
{
    const T INF = numeric_limits<T>::max();
    const T EPS = static_cast<T>(1.0e-10);

    dist.assign(edges.size(), INF);
    dist[start] = 0;
    priority_queue<pair<T,int>, vector<pair<T,int> >, greater<pair<T,int> > > q;
    q.push(make_pair(0, start));

    while(!q.empty()){
        pair<T, int> p = q.top();
        q.pop();
        int v = p.second;
        if(dist[v] < p.first - EPS)
            continue;
        for(unsigned i=0; i<edges[v].size(); ++i){
            EdgeBase<T> e = edges[v][i];
            if(dist[v] + e.cost < dist[e.to] - EPS){
                dist[e.to] = dist[v] + e.cost;
                q.push(make_pair(dist[e.to], e.to));
            }
        }
    }
}

int main()
{
    int n, m, p, q, t;
    cin >> n >> m >> p >> q >> t;
    -- p;
    -- q;

    vector<vector<Edge> > edges(n);
    for(int i=0; i<m; ++i){
        int a, b, c;
        cin >> a >> b >> c;
        -- a;
        -- b;
        edges[a].push_back(Edge(b, c));
        edges[b].push_back(Edge(a, c));
    }

    vector<long long> dist, dist_p, dist_q;
    shortestPath(edges, 0, dist);
    shortestPath(edges, p, dist_p);
    shortestPath(edges, q, dist_q);

    long long ans = -1;
    if(dist[p] + dist[q] + dist_p[q] <= t){
        ans = t;
    }
    else{
        for(int i=0; i<n; ++i){
            long long x = dist[i] * 2;
            long long y = dist_p[i] * 2;
            long long z = dist_q[i] * 2;
            if(x + max(y, z) > t)
                continue;
            ans = max(ans, t - max(y, z));
        }
    }
    cout << ans << endl;

    return 0;
}