// editor1
#include<iostream>
using namespace std;
int main()
{
    int a,b;
    cin>>a>>b;
    if(a<0||b<0){
        cout<<"Inavlid input";
    }else if (a%2==0 && b%2==0){
        cout<<a*b;
    }else if (a%2|=0  && b%2|=0){
        cout <<a+b;
    }else{
        cout<<abs(a-b);
    }
    }
    return 0;
}