题解 | #更相减损术#

import java.util.Scanner;

public class Main{
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int a = scan.nextInt();
        int b = scan.nextInt();
        int min = a <= b ? a : b;
        int max = a + b - min;
        while(max % min != 0){
            int cha = max - min;
            if(cha < min){
                min = cha;
                max = max - min;
            }else if(cha > min){
                min = min;
                max = cha;
            }
            
        }
        System.out.println(min);
    }    
}