// O(N^3 + QN log N)
#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#ifdef LOCAL
#include <debug.hpp>
#include <misc.hpp>
#else
#define debug(...)
#endif

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    int N, M, Q;
    cin >> N >> M >> Q;
    assert(N <= 1000 && M <= 1000 && Q <= 5000);
    vector<int> A(N), W;
    for (int i = 0; i < N; i++) cin >> A[i];
    constexpr int INF = (1 << 30) - 1;
    vector dist(N, vector<int>(N, INF));
    for (int i = 0; i < N; i++) dist[i][i] = 0;
    for (int i = 0; i < M; i++) {
        int u, v, w;
        cin >> u >> v >> w, u--, v--;
        dist[u][v] = dist[v][u] = w;
        W.emplace_back(w);
    }
    vector<int> S(Q), C(Q);
    for (int i = 0; i < Q; i++) cin >> S[i] >> C[i], S[i]--;

    ranges::sort(W);
    W.erase(ranges::unique(W).begin(), W.end());

    for (int k = 0; k < N; k++) {
        for (int from = 0; from < N; from++) {
            for (int to = 0; to < N; to++) {
                if (dist[from][k] == INF || dist[k][to] == INF) continue;
                dist[from][to] = min(dist[from][to], max(dist[from][k], dist[k][to]));
            }
        }
    }

    auto solve = [&](int s, int c) -> int {
        if (c == 1) return 0;  // 店 s 到達で ok
        int ok = ssize(W), ng = -1;
        while (ok - ng > 1) {
            int mid = midpoint(ok, ng);
            unordered_set<int> K;
            for (int t = 0; t < N; t++) {
                if (dist[s][t] <= W[mid]) K.emplace(A[t]);
            }
            (ssize(K) >= c ? ok : ng) = mid;
        }
        return (ok == ssize(W) ? -1 : W[ok]);
    };

    for (int i = 0; i < Q; i++) cout << solve(S[i], C[i]) << "\n";
}