// editor1
import java.util.Scanner;
class Main{
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        if(x<0 || y<0){
            System.out.println("Invalid input");
            return;
        }
        int x=sc.nextInt();
        int y=sc.nextInt();
        while(y!=0){
            int temp=y;
            y=x%y;
            x=temp;
            
        }
       System.out.println(x); 
    }
}