#include<bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define ll long long
#define llu unsigned long long
#define endl "\n"
#define rp(i,a,b) for(int i=a;i<=b;i++)
#define rep(i,a,b) for(int i=a;i<b;i++)
#define fp(i,a,b) for(int i=a;i>=b;i--)
#define IOS ios::sync_with_stdio(false),cout.tie(0),cin.tie(0);
const int INF = 1e9+10;
const ll mod = 998244353;
const int N = 1e5+6;
using namespace std;
typedef pair<int, int> PII;
inline __int128 read(){
    __int128 x=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9'){
        if(ch=='-')
            f=-1;
        ch=getchar();
    }
    while(ch>='0'&&ch<='9'){
        x=(x<<1)+(x<<3)+(ch^48);
        ch=getchar();
    }
    return x*f;
}
inline void write(__int128 x){
    if(x<0){
        putchar('-');
        x=-x;
    }
    if(x>9) write(x/10);
    putchar(x%10+'0');
}
ll ksm(ll a, ll b)
{
    ll res = 1;
    while(b > 0)
    {
        if (b & 1) res = res * a;
        a = a * a;
        b >>= 1;
    }
    return res;
}
void exgcd(int a, int b, int& x, int& y){
    if(b == 0){
        x=1,y=0;
        return;
    }
    exgcd(b,a%b,y,x);
    y-=a/b*x;
}

void c_prime(int n) {
    vector<ll> pri;
bool not_prime[500005];//用的时候两个数组都开全局//不是质数的标记
    for (int i = 2; i <= n; ++i){
        if(!not_prime[i]){
            pri.push_back(i);
      }
    for (int pri_j : pri) {
        if (i * pri_j > n) break;
        not_prime[i * pri_j] = true;
        if (i % pri_j == 0) {
            break;
      }
    }
  }
}
ll n,m,qq;
ll la[N];
vector<int>v[N];
ll ans;
queue<ll>q;
void bfs(ll p,ll lim,ll k)
{
    //bool flag=true;
    if(k>=n)
        return ;
    int cnt=v[p].size();
    rp(i,0,cnt-1)
    {
        q.push(v[p][i]);
    }
    //q.pop();
    while(cnt--)
    {
        if(la[q.front()]<=lim)
        {
            ans=min(ans,k);
            while(!q.empty())
            {
                q.pop();
            }
            return ;
        }
        else
        {
            int t=q.front();
            rp(i,0,(int)v[t].size()-1)
            {
                q.push(v[t][i]);
            }
            q.pop();
        }
    }
    if(!q.empty())
        bfs(q.front(),lim,k+1);
}
void solve() {
    
    cin>>n>>m>>qq;
    rp(i,1,n)
    {
        cin>>la[i];
    }
    //cout<<-1<<endl;
    rp(i,1,m)
    {
        ll x,y;
        cin>>x>>y;
        //cout<<x<<y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    //cout<<-1<<endl;
    while(qq--)
    {
        ll pp,x;
        //cout<<-1<<endl;
        cin>>pp>>x;
        //cout<<-1<<endl;
        ans=INF;
        //cout<<-1<<endl;
        if(la[pp]<=x)
        {
            cout<<0<<endl;
            return ;
        }
        bfs(pp,x,1);
        if(ans!=INF)
            cout<<ans<<endl;
        else
            cout<<-1<<endl;
        while(!q.empty())
        {
            q.pop();
        }
    }
    //cout<<-1<<endl;
}
signed main()
{
    //IOS
    int TT = 1;
    //cin>>TT;
    while (TT--)
    {
        solve();
    }
    return 0;
}