#include <iostream>
using namespace std;
int a,b;
int lcm(int a,int b){
    for(int i = 1;i <= a * b;++i){
        if(i % a == 0 && i % b == 0){
            return i;
        }
    }
    return -1;
}
int main(){
    cin >> a >> b;
    cout << lcm(a,b) << endl;
    return 0;
}