#include<iostream>
using namespace std;
int main()
{
    int A
    int B;
    cin<<A;
    cin<<B;
    if(((A+1%2)>0)&&((B+1%2)>0))
    {
        cout<<(A-B);
    }
    else if((A%2==0)&&(B%2==0))
    {
        cout<<(A+B);
        
    }
    else if((((A+1%2)>0)&&(B%2==0))||((A%2==0))&&((B+1%2)>0))
    {
        cout<<(A/B);
    }
    return 0;
}