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

const long long INF = 1e18;

struct State {
    long long cost;
    int u, fuel;
    bool operator>(const State& other) const {
        return cost > other.cost;
    }
};

long long dist[1005][105];

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n, m, c, s, t;
    if (!(cin >> n >> m >> c >> s >> t)) return 0;
    vector<long long> p(n + 1);
    for (int i = 1; i <= n; i++) cin >> p[i];
    vector<vector<pair<int, int>>> adj(n + 1);
    for (int i = 0; i < m; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].push_back({v, w});
    }

    for (int i = 1; i <= n; i++) {
        for (int f = 0; f <= c; f++) {
            dist[i][f] = INF;
        }
    }

    priority_queue<State, vector<State>, greater<State>> pq;
    dist[s][0] = 0;
    pq.push({0, s, 0});

    while (!pq.empty()) {
        auto [cost, u, fuel] = pq.top();
        pq.pop();
        if (cost > dist[u][fuel]) continue;

        // Option 1: Buy 1 unit of fuel at u if there is a charging station
        if (p[u] > 0 && fuel < c) {
            if (cost + p[u] < dist[u][fuel + 1]) {
                dist[u][fuel + 1] = cost + p[u];
                pq.push({dist[u][fuel + 1], u, fuel + 1});
            }
        }

        // Option 2: Go to adjacent nodes
        for (auto& edge : adj[u]) {
            int v = edge.first;
            int w = edge.second;
            if (fuel >= w) {
                if (cost < dist[v][fuel - w]) {
                    dist[v][fuel - w] = cost;
                    pq.push({dist[v][fuel - w], v, fuel - w});
                }
            }
        }
    }
    long long ans = INF;
    for (int f = 0; f <= c; f++) {
        ans = min(ans, dist[t][f]);
    }
    cout << (ans == INF ? -1 : ans) << "\n";
    return 0;
}