#include <iostream>
#include <fstream>

using namespace std;

long long find(long long P, long long Q){
    long long counter = 0;

    for(long long i = 1; i <= INT64_MAX; i++ )
    {
        if( i % P == 0 )
        {
            counter = counter + i/P;
        }
        if(counter == Q){
            return i;
        }
    }
    return -1;
}

int main() {
    long long P,Q;
    long long A;

    ifstream in("gfact.in");
    ofstream out("gfact.out");

    in >> P >> Q;

    out << find(P,Q);

    return 0;
}