import java.util.*;
import java.lang.*;
import java.io.*;

// The main method must be in a class named "Main".
class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        int n2=sc.nextInt();
        while (n2!=0) {
            int temp=n2;
            n2=n%n2;
            n=temp;
        }
        System.out.println(n);
    }
}