#include<stdio.h>
#include<iostream>
#include<cstring>
#include<algorithm>
using namespace std;
int a[110];
int main()
{
	//freopen("random.in","r",stdin);  
	//freopen("random.out","w",stdout);
	int sum=0,rec,p,q,n,i,j;
	scanf("%d\n",&n);
	
	for(i=1;i<=n;i++)
	{
		scanf("%d\n",&a[i]);
	}//i是组长 
	
	for(p=1;p<=i;p++)
	{
		for(q=p+1;q<=i;q++)
		{
			if(a[p]==a[q])
			{
				rec=q;
				while(q<=i)
				{
					a[q]=a[q+1];
					q++;
				}
				q=rec;
				i=i-1;
			}
		}
	}//i还是组长 
	sort(a+1,a+1+i);
	printf("%d\n",i);
	for(j=1;j<=i;j++)
	{
		printf("%d",a[j]);
	}
	printf("\n");
	return 0;
}
//20 40 32 67 40 20 89 300 400 15