#include<iostream>
using namespace std;
int main(){
    int A,B;
    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;
}