1389A_LCM Problem.cpp

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main()
{
    int t;
    cin >> t;

    while (t--)
    {
        int l, r;
        cin >> l >> r;
        if (l * 2 > r)
        {
            cout << "-1 -1" << endl;
        }
        else
        {
            cout << l << " " << l * 2 << endl;
        }
    }

    return 0;
}