/*
 * This code is from "Algorithms in C, Third Edition,"
 * by Robert Sedgewick, Addison Wesley Longman, 1998.
 */
#include <stdio.h>
#include <stdlib.h>

int gcd(int, int);

int main(int argc, char *argv[])
{
  printf("%d\n", gcd(atoi(argv[1]), atoi(argv[1])));
  return 0;
}

int gcd(int m, int n)
  {
    if (n == 0) return m;
    return gcd(n, m % n);
  }