#include <iostream>
#include <cstdio>
#include <algorithm>
#include <functional>
#include <queue>
#include <utility>
#include <vector>

using namespace std;

typedef long long LL;
typedef pair<int, int> PII;
typedef pair<LL, int> PLI;

const int N = 2010;
const LL INF = 0x3f3f3f3f3f3f3f3fLL;

vector<PII> g[N];
priority_queue<PLI, vector<PLI>, greater<PLI>> pq;
LL d1[N], dp[N], dq[N], ans;
int n, m, p, q, t;

void Dijkstra(int bg, LL dist[]) {
    fill(dist + 1, dist + n + 1, INF);
    dist[bg] = 0LL;
    pq.push({ 0LL, bg });
    while (!pq.empty()) {
        auto [dis, u] = pq.top();
        pq.pop();
        if (dis != dist[u]) continue;
        for (auto [v, w] : g[u]) {
            if (dist[v] <= dis + w) continue;
            dist[v] = dis + w;
            pq.push({ dist[v], v });
        }
    }
}

int main() {
    // freopen("friend.in", "r", stdin);
    // freopen("friend.out", "w", stdout);

    scanf("%d%d%d%d%d", &n, &m, &p, &q, &t);
    for (int i = 1, a, b, c; i <= m; ++i) {
        scanf("%d%d%d", &a, &b, &c);
        g[a].push_back({ b, c });
        g[b].push_back({ a, c });
    }

    Dijkstra(1, d1);
    Dijkstra(p, dp);
    Dijkstra(q, dq);

    if (d1[p] + dp[q] + d1[q] <= t) {
        printf("%d\n", t);
        return 0;
    }

    ans = -1LL;
    for (int x = 1; x <= n; ++x) {
        for (int y = x; y <= n; ++y) {
            LL sep = max(dp[x] + dp[y], dq[x] + dq[y]);
            if (d1[x] + sep + d1[y] <= t) ans = max(ans, 1LL * t - sep);
        }
    }

    printf("%lld\n", ans);

    return 0;
}