#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main()
 {
  int A,B,x;

  freopen("adunare.in","r",stdin);
  freopen("adunare.out","w",stdout);

  scanf("%d%d", &A,&B);

  srand(A+B);

  while(A!=0 && B!=0)
   {
    x = rand()&1;
    
    if(rand()&1)
     A-=x, B+=x;
      else
     A+=x, B-=x;
   }

  if(A)
   printf("%d\n", A);
    else
   printf("%d\n", B);

  return 0;
 }