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

constexpr int INF = 1'000'000'009;

struct Edge{
    int to;
    int cost;
    Edge(int to, int cost):to(to), cost(cost) {}
};

vector<int> dijkstra(int start, const vector<vector<Edge>> &Es, const int distlimit){
    int N = Es.size();
    vector<int> dist(N, INF);
    dist[start] = 0;
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    pq.push(make_pair(0, start));
    while (not pq.empty()){
        int d, v;
        tie(d, v) = pq.top();
        pq.pop();
        if (d > dist[v]) continue;
        dist[v] = d;
        for (auto &uc : Es[v]){
            int u = uc.to;
            int new_d = d + uc.cost;
            if (new_d < dist[u] and new_d <= distlimit){
                dist[u] = new_d;
                pq.push(make_pair(new_d, u));
            }
        }
    }
    return dist;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N, M, P, Q, T;
    cin >> N >> M >> P >> Q >> T;
    --P;
    --Q;
    vector<vector<Edge>> Es(N, vector<Edge>());
    for (int m = 0; m < M; ++m){
        int a, b, c;
        cin >> a >> b >> c;
        Es[a - 1].emplace_back(Edge(b - 1, c));
        Es[b - 1].emplace_back(Edge(a - 1, c));
    }
    auto dist0 = dijkstra(0, Es, T);
    auto distP = dijkstra(P, Es, T);
    auto distQ = dijkstra(Q, Es, T);
    if (dist0[P] + distP[Q] + distQ[0] <= T){
        cout << T << endl;
        return 0;
    }
    long long record = -1;
    for (int r = 0; r < N; ++r){
        long long t = max(distP[r], distQ[r]);
        if ((dist0[r] + t) * 2 <= T) record = max(record, T - t * 2);
    }
    cout << record << endl;
    return 0;
}