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