#include<stdio.h>
void swap(int *a, int *b)
{
    int t = *a;
    *a = *b;
    *b = t;
} 

int main()
{
    int x, y;
    scanf("%d%d", &x,&y);
    int(x < 0 || y < 0)printf("Invalid Input\n");
    else{
        swamp(&x, &y);
        p
    }
}