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