//qoj6772
#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 10;
int n, m, q, w[N], ds[103][N], vs[N];
vector<int> g[N], nd[110];

int main(){
    scanf("%d%d%d", &n, &m, &q);
    for(int i = 1; i <= n; ++ i){
        scanf("%d" ,&w[i]);
        nd[w[i]].push_back(i);
    }
    for(int i = 1; i <= m; ++ i){
        int u, v;
        scanf("%d%d", &u, &v);
        g[u].push_back(v);
        g[v].push_back(u);
    }
    memset(ds, 0x3f ,sizeof(ds));
    for(int i = 1; i <= 100; ++ i){
        queue<int> q;
        memset(vs, 0, sizeof(vs));
        for(int j = 1; j <= n; ++ j){
            if(w[j] <= i){
                q.push(j);
                ds[i][j] = 0;
            }
        }
        while(!q.empty()){
            int x = q.front();
            q.pop();
            if(vs[x]) continue;
            vs[x] = 1;
            for(int y : g[x]){
                if(ds[i][y] > ds[i][x] + 1){
                    ds[i][y] = ds[i][x] + 1;
                    q.push(y);
                }
            }
        }
    }
    while(q--){
        int x, y;
        scanf("%d%d", &x, &y);
        printf("%d\n", ds[y][x] == 0x3f3f3f3f ? -1 : ds[y][x]);
    }
    return 0;
}