#include <iostream>
#include <cmath>
using namespace std;

int main() {
    int A,B;
    cin >>A>>B;
    
    if (A,0 || B<0){
        cout << "invaild 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;
{