#include <stdio.h>

int pgcd(int a, int b)
{
  int c;

  if (a > b)
    {
      c = a;
      a = b;
      b = c;
    }

  while (a != 0)
    {
      c = a;
      a = b % a;
      b = c;
    }

  return b;
}

int main(int argc, char *argv[])
{
  int a, b;

  if (argc != 3 ||
      sscanf(argv[1], "%d", &a) != 1 ||
      sscanf(argv[2], "%d", &b) != 1)
    return -1;

  printf("%d\n", pgcd(a, b));

  return 0;
}