#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll INF = 1e18;
using T = tuple<ll, int, int>;

int main() {
    int N, M, K;
    cin >> N >> M >> K;

    vector<ll> C(M);
    for (int i = 0; i < M; ++i) {
        cin >> C[i];
    }

    vector<vector<pair<int, ll>>> G(N + 1);
    for (int i = 0; i < M; ++i) {
        int u, v;
        cin >> u >> v;
        G[u].emplace_back(v, C[i]);
        G[v].emplace_back(u, C[i]);
    }

    vector<vector<ll>> dist(N + 1, vector<ll>(K + 1, INF));
    priority_queue<T, vector<T>, greater<>> pq;

    dist[1][0] = 0;
    pq.emplace(0, 1, 0);

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

        for (auto &[v, c] : G[u]) {

            if (dist[v][used] > cost + c) {
                dist[v][used] = cost + c;
                pq.emplace(dist[v][used], v, used);
            }
            if (used < K && dist[v][used + 1] > cost) {
                dist[v][used + 1] = cost;
                pq.emplace(dist[v][used + 1], v, used + 1);
            }
        }
    }

    ll ans = *min_element(dist[N].begin(), dist[N].end());
    cout << ans << '\n';

    return 0;
}