# include <stdio.h>
# include <stdlib.h>
# include <time.h>

int i, j, n, k;
int a[105];
int b[105];

void sort1(int * a, int len);

int main()
{   
    scanf("%d", &n);
   	srand((unsigned)time(NULL));
    
	for (i=0; i<n; ++i)
		a[i] = rand() % 1001 + 1;
	sort1(a, n);
	for (i=0; i<n; ++i)
	{
		if (a[i] == a[i+1])
		   continue;
		else
		    {
		    	b[k] = a[i];
			    ++k;
			}
	} 
	
	printf("%d\n", k);
	for (i=0; i<k; ++i)
	    printf("%d ", b[i]);
    
	
	return 0;
}
void sort1(int * a, int len)
{
	int t;
	for (i=0; i<len-1; ++i)
	{
		for (j=0; j<len-i-1; ++j)
		{
			if (a[j]>a[j+1])
			{
				t = a[j];
				a[j] = a[j+1];
				a[j+1] = t;
			}
		}
	}
	
}