//
#include<iostream>
#include<cmath)
using namespace std;
int main() {
    int a,b;
    cin>>a>>b;
    if(a<0||b<0){
        cout<<"Invalid input"<<endl;
        return 0;
    }
    if(a % 2 == 00  && b % 2 == 0){
    cout<<a*b<<endl;
}
else if(a % 2 != 00 && b % 2 !=0){
    cout<<a+b<<endl;
}
else{
    cout<<abs(a-b)<<endl;
}
return 0;
}