#include <bits/stdc++.h>

using namespace std;

int main(){
    int q;
    cin >> q;
    for(int a0 = 0; a0 < q; a0++){
        int len;
        int c;
        cin >> len >> c;
        cout <<"-1"<<"\n";
        // your code goes here
    }
    return 0;
}