#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, b, a) for(int i = (b) - 1; i >= (a); i--)
#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;
typedef double db;

const int N = 1 << 17;
int w[N];
VI g[N];

int d[N];

void upd(int v)
{
	d[v] = 0;
	queue<int> q;
	q.push(v);
	
	while(!q.empty())
	{
		v = q.front();
		q.pop();
		for(int to : g[v])
		{
			if(d[to] > d[v] + 1)
			{
				d[to] = d[v] + 1;
				q.push(to);
			}
		}
	}
}



int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);
	cout << fixed << setprecision(15);
	fill(d, d + N, 1e9);
	
	int n, m, q;
	cin >> n >> m >> q;
	
	FOR(i, 0, n)
		cin >> w[i];
	
	FOR(i, 0, m)
	{
		int a, b;
		cin >> a >> b;
		a--; b--;
		g[a].PB(b);
		g[b].PB(a);
	}
	
	vector<PII> query(q);
	FOR(i, 0, q)
	{
		int c, a;
		cin >> c >> a;
		c--;
		query[i] = MP(c, a);
	}
	VI ans(q, -1);
	
	FOR(val, 1, 101)
	{
		FOR(v, 0, n)
		{
			if(w[v] == val)
				upd(v);
		}
		FOR(i, 0, q)
		{
			if(query[i].S == val)
				ans[i] = d[query[i].F];
		}
	}
	FOR(i, 0, q)
	{
		if(ans[i] > n)
			ans[i] = -1;
			
		cout << ans[i] << "\n";
	}
	
	
	
	
	
	
	
	
	return 0;
}