#include <iostream>
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
int n, q;
cin >> n >> q;
vector<int> book(n);
for( int i = 0; i < n; i++ ) cin >> book[i];
sort( book.begin(), book.end() );
while( q-- )
{
int len, x;
cin >> len >> x;
int mod = 1;
for( int i = 0; i < len; i++ ) mod *= 10;
int ans = -1;
for( int num : book )
{
if( num % mod == x )
{
ans = num;
break;
}
}
cout << ans << endl;
}
return 0;
}
