#include <iostream>
#include <vector>
#include <queue>
using namespace std;
const int N = 5e5 + 10, M = 105;
int n, m,t, w[N],vis[N],dist[N][M];
vector<int>a[N];
void bfs(int val) {
	queue<int>q;
	for (int i = 1; i <= n; i++) {
		vis[i] = 0;
		dist[i][val] = 1e9;
		if (w[i] == val) {
			dist[i][val] = 0;
			q.push(i);
		}
	}
	while (!q.empty()) {
		int u = q.front();
		q.pop();
		if (vis[u])continue;
		vis[u] = 1;
		for (int i = 0; i < a[u].size(); i++) {
			int v = a[u][i];
			if (!vis[v] && dist[v][val] > dist[u][val] + 1) {
				dist[v][val] = dist[u][val] + 1;
				q.push(v);
			}
		}
	}
}
int main() {
	cin >> n >> m >> t;
	for (int i = 1; i <= n; i++)
		cin >> w[i];
	for (int i = 1; i <= m; i++) {
		int u, v;
		cin >> u >> v;
		a[u].push_back(v);
		a[v].push_back(u);
	}
	for (int i = 1; i <= n; i++)
		bfs(i);
	while (t--) {
		int pos, k;
		cin >> pos >> k;
		int ans = 1e9;
		for (int i = 1; i <= k; i++)
			ans = min(ans, dist[pos][i]);
		if (ans == 1e9)cout << "-1\n";
		else cout << ans << "\n";
	}
}