/* Code of Figure 11.3, page 477 from
   Kenneth C. Louden, Programming Languages
   Principles and Practice 2nd Edition
   Copyright (C) Brooks-Cole/ITP, 2003
*/

#include <stdio.h>

int gcd (int u, int v)
{ int t1, t2; /* temps introduced by translator */
  for(;;)
  { if (v == 0) return u;
    else
    { t1 = v;
      t2 = u % v;
      u = t1;
      v = t2;
    }
  }
}

main()
{ int u, v, x;
  scanf("%d %d",&u,&v);
  x = gcd(u,v);
  printf("%d\n",x);
  return 0;
}