#include <algorithm>
#include <iostream>
#include <vector>
#include <queue>
#include <tuple>
using namespace std;
const long long INF = 1LL << 60;    // 1.15x10^18
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using edge = pair<int, long long>;
using Graph = vector<vector<edge>>;

vector<long long> dijkstra(const Graph &g, int s) {
    vector<long long> dist(g.size(), INF);
    using Pi = pair<long long, int>;
    priority_queue<Pi, vector<Pi>, greater<Pi>> que;
    dist[s] = 0; que.emplace(dist[s], s);
    while (!que.empty()) {
        long long cost; int u; tie(cost, u) = que.top(); que.pop();
        if (dist[u] < cost) continue;
        for (auto &e: g[u]) {
            int v; long long nc; tie(v, nc) = e;
            if (chmin(dist[v], dist[u] + nc)) que.emplace(dist[v], v);
        }
    }
    return dist;
}

int main() {
    int N, M, P, Q, T; cin >> N >> M >> P >> Q >> T; P--, Q--;
    Graph g(N);
    while (M--) {
        int a, b, c; cin >> a >> b >> c; a--, b--;
        g[a].emplace_back(b, c);
        g[b].emplace_back(a, c);
    }
    auto d = dijkstra(g, 0);
    auto p = dijkstra(g, P);
    auto q = dijkstra(g, Q);
    if (d[P] + p[Q] + q[0] <= T) return !(cout << T << endl);
    int ans = -1;
    for (int u = 0; u < N; u++) for (int v = 0; v < N; v++) {
        int alone = max(p[u] + p[v], q[u] + q[v]);
        if (d[u] + alone + d[v] <= T) ans = max(ans, T - alone);
    }
    cout << ans << endl;
    return 0;
}