#include <stdio.h>

const int m1  = 1431655765; // binary: 0101...
const int m2  = 858993459; // binary: 00110011...
const int m4  = 252645135; // binary: 0000111100001111...

int main()
{
  int a, b;

  scanf("%d %d", &a, &b);

  int result = a ^ b;

  result = (result & m1 ) + ((result >>  1) & m1 ); //put count of each  2 bits into those  2 bits
  result = (result & m2 ) + ((result >>  2) & m2 ); //put count of each  4 bits into those  4 bits
  result = (result & m4 ) + ((result >>  4) & m4 ); //put count of each  8 bits into those  8 bits

  printf("%d", 7 - result);

  return 0;
}