#include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int l, r;       cin >> l >> r;       if (l * 2 <= r) {         cout << l <<     << l * 2 << endl;       } else {         cout << -1 <<     << -1 << endl;       }     }     return 0;   }   