import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long a = sc.nextLong();
    long b = sc.nextLong();
    System.out.println(gcd(a, b));
  }

  public static long gcd(long a, long b) {
    if(b == 0) return a;
    return gcd(b, (a % b));
  }
}