#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define watch(x) cout<<(#x)<<"="<<(x)<<'\n'
#define mset(d,val) memset(d,val,sizeof(d))
#define cbug if(DEBUG) cout
#define setp(x) cout<<fixed<<setprecision(x)
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define forn(i,a,b) for(int i=(a);i<(b);i++)
#define fore(i,a,b) for(int i=(a);i<=(b);i++)
#define pb push_back
#define F first
#define S second
#define fbo find_by_order
#define ook order_of_key
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> ii;
typedef vector<ll> vi;
typedef vector<ii> vii;
//template<typename T>
//using pbds = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
void SD(int t=0){ cout<<"PASSED "<<t<<endl; }
ostream& operator<<(ostream &out, ii x){ out<<"("<<x.F<<","<<x.S<<")"; return out; }
template<typename T> void amax(T &a, T b){ a=max(a,b); }
template<typename T> void amin(T &a, T b){ a=min(a,b); }
struct Hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }
    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

const ll INF = ll(1e18);
const int MOD = 998244353;
const bool DEBUG = 0;
const int MAXN = 100005;
const int LG = 21;

int n,m,Q;
vector<vector<int>> adj;
vector<int> w;
vector<vector<int>> dist;

int main()
{
    cin.tie(0)->sync_with_stdio(0);

    cin>>n>>m>>Q;
    adj.resize(n);
    w.resize(n);
    dist.resize(100, vector<int>(n, 1e9));

    forn(i,0,n)
    {
        cin>>w[i]; w[i]--;
    }

    forn(i,0,m)
    {
        int u,v; cin>>u>>v; u--; v--;
        adj[u].pb(v);
        adj[v].pb(u);
    }

    forn(i,0,100)
    {
        queue<int> q;
        forn(u,0,n)
        {
            if (w[u] <= i)
            {
                q.push(u);
                dist[i][u] = 0;
            }
        }
        while (!q.empty())
        {
            int u = q.front();
            q.pop();
            for (int v : adj[u])
            {
                if (dist[i][v] < 1e9) continue;
                dist[i][v] = dist[i][u] + 1;
                q.push(v);
            }
        }
    }

    forn(i,0,Q)
    {
        int u, x; cin >> u >> x; u--; x--;
        cout<<(dist[x][u] >= 1e9 ? -1 : dist[x][u])<<'\n';
    }

    return 0;
}