#include <queue>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
const long long inf = 1LL << 62;
struct edge {
	int to; long long cost;
};
struct state {
	int pos; long long cost;
};
bool operator<(const state& s1, const state& s2) {
	return s1.cost > s2.cost;
}
int main() {
	int N, M, P, Q; long long T;
	cin >> N >> M >> P >> Q >> T; --P, --Q;
	vector<vector<edge> > G(N);
	for (int i = 0; i < M; ++i) {
		int a, b; long long c;
		cin >> a >> b >> c; --a, --b;
		G[a].push_back(edge{ b, c });
		G[b].push_back(edge{ a, c });
	}
	vector<vector<long long> > dist(N, vector<long long>(N, inf));
	for (int i = 0; i < N; ++i) {
		dist[i][i] = 0;
		priority_queue<state> que;
		que.push(state{ i, 0 });
		while (!que.empty()) {
			int u = que.top().pos; que.pop();
			for (edge e : G[u]) {
				if (dist[i][e.to] > dist[i][u] + e.cost) {
					dist[i][e.to] = dist[i][u] + e.cost;
					que.push(state{ e.to, dist[i][e.to] });
				}
			}
		}
	}
	if (dist[0][P] + dist[P][Q] + dist[Q][0] <= T) {
		cout << T << endl;
	}
	else {
		long long ans = -1;
		for (int i = 0; i < N; ++i) {
			long long div = max(dist[i][P], dist[i][Q]) * 2;
			if (div + dist[0][i] * 2 <= T) {
				ans = max(ans, T - div);
			}
		}
		cout << ans << endl;
	}
	return 0;
}