#include <iostream>
#include <vector>
#include <queue>
using namespace std;
using vi = vector<int>;

const int mn = 1e5+1;
const int mm = 1e5+1;
const int mq = 5e5+1;
const int mw = 101;
const int inf = 1e6;

int ans[mn][mw];
vi adj[mn];
int w[mn];

int main() {
	int n, m, q; cin >> n >> m >> q;
	for (int i = 1; i <= n; i++) {
		cin >> w[i];
		for (int j = 0; j < mw; j++) ans[i][j] = inf;
	}
	for (int i = 0; i < m; i++) {
		int u, v; cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}

	for (int curW = 1; curW < mw; curW++) {
		queue<int> q;
		for (int i = 1; i <= n; i++) {
			if (w[i] <= curW) {
				q.push(i);
				ans[i][curW] = 0;
			}
		}
		while (q.size()) {
			int top = q.front();
			q.pop();
			for (int i : adj[top]) {
				if (ans[i][curW] == inf) {
					ans[i][curW] = ans[top][curW] + 1;
					q.push(i);
				}
			}
		}
	}

	for (int i = 0; i < q; i++) {
		int x, y; cin >> x >> y;
		if (ans[x][y] == inf) cout << -1 << '\n';
		else cout << ans[x][y] << '\n';
	}
}