#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N = 100005;
const int M = 100;
const int INF = 0x3f3f3f3f;
int s[N];
//int dist[N][M];
vector<vector<int>> dist(N, vector<int>(105, INF));
vector<int> gp[N];
void bfs(int la, int d)
{
	vector<int> vis(N);
	queue <int> q;
	for (int i = 1; i <= d; i++)
	{
		if (s[i] == la)
		{
			dist[i][la] = 0;
			q.push(i);
			vis[i] = 1;

		}
	}
	while (!q.empty())
	{
		int fr = q.front();
		q.pop();
		for (auto i: gp[fr])
		{
			if (!vis[i])
			{
				q.push(i);
				dist[i][la] = dist[fr][la] + 1;
				vis[i] = 1;
			}
		}
	}
}
signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n, m, q;
	cin >> n >> m >> q;
	//memset(dist, INF, sizeof(dist));
	for (int i = 1; i <= n; ++i)
	{
		cin >> s[i];
	}
	for (int i = 0; i < m; ++i)
	{
		int u, v;
		cin >> u >> v;
		gp[u].push_back(v);
		gp[v].push_back(u);
	}
	for (int sv = 1; sv <= M; ++sv)
	{
		bfs(sv, n);
	}
	while (q--)
	{
		int p, a;
		cin >> p >> a;
		int ans = INF;
		for (int i = 1; i <= a; i++)
		{
			if (dist[p][i] == INF) continue;
			ans = min(ans, dist[p][i]);
		}
		if (ans == INF) cout << -1 << endl;
		else cout << ans << endl;
	}
	return 0;
	
}