#include<stdio.h>

void swap (int *xp, int *yp) 
{
    int  temp = *xp;
    *xp = *yp;
    *yp = temp;
}

int main()
{
    int x, y;
    
    if (scanf("%d %d", &x, &y) ! = 2) {
        printf("Invalid input\n");
        return 1;
    }
    
    if (x < 0 || y < 0) {
        printf("Invalid input\n");
        return 1;
    }
    
    swap (&x, &y);
    
    printf ("%d\n", x);
    printf ("%d\n", y);
    
    return 0;
}