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