#include<stdio.h>
#include<time.h>
#include<stdlib.h>
int main()
{
	int N, a[100],i=0,j,k;
	scanf("%d", &N);
	srand((unsigned)time(NULL));
	while (i < N)
	{
		a[i] = rand()%1001;
		i++;
	}
	for (j = 0;j<=N-1; j++)
		for(i=0;i<=N-1-j;i++)	
		{
			if (a[i] > a[i + 1])
			{
				k = a[i];
				a[i] = a[i + 1];
				a[i + 1] = k;
			}
		}
	for (i = 0; i < N; i++)
	{
		if (a[i] = a[i + 1])
		{
			for (; i < N-2; i++)
				a[i+1] = a[i+2];
			N--;
		}
	}
	printf("%d\n", N);
	for (i = 0; i < N; i++)
	printf("%d ", a[i]);

}