#include <bits/stdc++.h>
#define int long long

using namespace std;

constexpr int inf = 1E18;

void solve () {
    int n, m, q;
    cin >> n >> m >> q;

    vector <int> w (n);
    for (int i = 0; i < n; i ++) {
        cin >> w[i];
        w[i] --;
    }

    vector <vector <int>> e (n);
    for (int i = 0; i < m; i ++) {
        int x, y;
        cin >> x >> y;
        x --; y --;
        e[x].push_back (y);
        e[y].push_back (x);
    }

    vector dis (n, array <int, 100> {});
    for (int t = 0; t < 100; t ++) {
        queue <int> q;
        for (int i = 0; i < n; i ++) {
            if (w[i] <= t) {
                q.push (i);
                dis[i][t] = 0;
            } else {
                dis[i][t] = inf;
            }
        }
        while (q.size ()) {
            auto x = q.front ();
            q.pop ();

            for (auto y : e[x]) {
                if (dis[y][t] > dis[x][t] + 1) {
                    dis[y][t] = dis[x][t] + 1;
                    q.push (y);
                }
            }
        }
    }

    while (q --) {
        int x, d;
        cin >> x >> d;
        x --;
        d --;

        if (dis[x][d] == inf) {
            cout << -1 << '\n';
        } else {
            cout << dis[x][d] << '\n';
        }
    }
}

signed main () {
    ios::sync_with_stdio (false);
    cin.tie (nullptr);

    int T = 1;
    // cin >> T;

    while (T --) {
        solve ();
    }

    return 0;
}