import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int b = scanner.nextInt();
        int a = scanner.nextInt();

        //write your code here.......
        

        System.out.println(a+" "+b);
    }
}

我们观察输入输出,即可发现,交换a和b的输入即可,整个代码只需要改动两个单词即可AC!