/*
Author: haze
2023/11/15
10:40
*/

#include <bits/stdc++.h>

#define irep(i, l, r) for(int (i) = (l); (i) <= (r); ++(i))
#define drep(i, r, l) for(int (i) = (r); (i) >= (l); --(i))
#define ll long long
#define LL __int128
using namespace std;

inline ll read() {
    char ch = getchar();
    ll s = 0;
    bool w = 0;
    while (!isdigit(ch)) {
        if (ch == '-')w = 1;
        ch = getchar();
    }
    while (isdigit(ch))s = (s << 3) + (s << 1) + (ch ^ 48), ch = getchar();
    return w ? -s : s;
}

inline char rc() {
    char ch = getchar();
    while (1) {
        if (ch >= '!' && ch <= '~')return ch;
        ch = getchar();
    }
}

template<class T1, class T2>
T1 min(T1 AA, T2 BB) { return AA > BB ? BB : AA; }

template<class T1, class T2>
T1 max(T1 AA, T2 BB) { return AA < BB ? BB : AA; }

const int itinf = 1e9;
const ll llinf = 4e18;
const int mod = 1000000007;
const int N = 500009;

int main() {
    int n = read(), m = read(), Q = read();
    vector<int>a[100], dis[100];
    vector<vector<int>>g(n);
    irep(i, 0, n - 1){
        a[read() - 1].emplace_back(i);
    }

    irep(i, 0, m - 1){
        int u = read() - 1, v = read() - 1;
        g[u].emplace_back(v);
        g[v].emplace_back(u);
    }

    irep(id, 0, 99){
        irep(i, 0, n - 1){
            dis[id].emplace_back(mod);
        }
        deque<int>q;
        for(int x : a[id]){
            dis[id][x] = 0;
            q.push_back(x);
        }
        while(q.size()){
            int x = q.front();
            q.pop_front();
            for(int y : g[x]){
                if(dis[id][y] == mod){
                    q.push_back(y);
                    dis[id][y] = dis[id][x] + 1;
                }
            }
        }
    }
    irep(d, 1, 99){
        irep(i, 0, n - 1){
            dis[d][i] = min(dis[d][i], dis[d - 1][i]);
        }
    }
    while(Q --){
        int u = read() - 1, lim = read() - 1;
        if(dis[lim][u] == mod)puts("-1");
        else printf("%lld\n", dis[lim][u]);
    }
    return 0;
}