#include <iostream>
using namespace std;
void calculateResult(int A,int B)
{
 if(A<0||B<0)
 {
  out<<"Invalid input";
  return;
 }
 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;
}