#include <iostream>
using namespace std;
void calculateResult(int A, int B){
    if(A<0||B<0){
        cout<<"Invalid input";
        return;
    }
    if(A % 2==0&&B % 2==0){
        cout<<A*B;
    }
    else if(A % 2!=0||B % 2!=0){
        cout<<A+B;
    }
    else{
        cout<<B-A;
    }
    
}
int main()
{
    int A,B;
    cin>>A;
    cin>>B;
    claculateResul(A,B);
    return 0;
}