#include<iostream>
#include<cmath>
using namespace std;
int n,q,book[6666],len[6666],num[6666];

int main()
{
    cin>>n>>q;
    for(int i=1; i<=n; i++) cin>>book[i];
    for(int i=1; i<=q; i++) {
        cin>>len[i]>>num[i];
        int tmp = pow(10,len[i]),min = 10000001;
        for(int j=1; j<=n; j++) if(book[j] % tmp == num[i] && book[j] < min) min = book[j];
        if(min != 10000001) cout<<min<<endl;
        else cout<<-1<<endl; 
    }
    return 0;
}