#include <iostream>

using namespace std;

int main() {
   int a,b;
   cin >>a>>b;
   if ((a*b)/2%2==0)
   cout << 0; 
   if((a*b)/2%2==1)
   if (a>b) 
   cout <<b;
   else 
   cout <<a;
  return 0;
}