#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <vector>
#include <map>
#include <unordered_set>
#include <unordered_map>

#define x first
#define y second
#define IOS ios::sync_with_stdio(false);cin.tie(0);

using namespace std;

typedef long long LL;
typedef pair<int, int> PII;

const int N = 110, M = 100010, MOD = 1000000007, INF = 0x3f3f3f3f;

int n, m, q;
int e[2 * M], ne[2 * M], h[M], idx;
int w[M];
int dist[M][N]; //dist[i][j]表示距离i最近的属性值恰好为j的点的距离
bool st[M];

void add(int a, int b)
{
    e[idx] = b, ne[idx] = h[a], h[a] = idx++;
}

void bfs(int v)
{
    memset(st, 0, sizeof st);
    queue<int> q;
    for (int i = 1; i <= n; i++)
        if (w[i] == v)
        {
            q.push(i);
            st[i] = true;
            dist[i][v] = 0;
        }

    while (!q.empty())
    {
        auto t = q.front();
        q.pop();

        for (int i = h[t]; i != -1; i = ne[i])
        {
            int j = e[i];
            if (st[j])
                continue;

            st[j] = true;
            dist[j][v] = dist[t][v] + 1;
            q.push(j);
        }
    }
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    memset(h, -1, sizeof h);
    cin >> n >> m >> q;
    for (int i = 1; i <= n; i++)
        cin >> w[i];

    while (m--)
    {
        int a, b;
        cin >> a >> b;
        add(a, b), add(b, a);
    }

    for (int i = 1; i <= n; i ++ )
        for (int j = 1; j <= 100; j ++ )
            dist[i][j] = INF; //注意dist的初始化不能在bfs里面,且memset会超时

        for (int i = 1; i <= 100; i++)
            bfs(i);

    while (q--)
    {
        int cur, v;
        cin >> cur >> v;
        int res = INF;
        for (int i = 1; i <= v; i++)
            res = min(res, dist[cur][i]);

        if (res == INF)
            cout << -1 << endl;
        else
            cout << res << endl;
    }

    return 0;
}