#include<stdio.h>
int main()
{
    int num1,num2;
    scanf("%d",&num1);
    scanf("%d",&num2);
    if(num1&&num2<0){
        printf("Invalid input");
        break;
    }
    int temp=num1;
    num1=num2;
    num2=temp;
    printf("%d %d",num1,num2);
    return 0;
}