记录

#include <cstdio>
#include <iostream>
using namespace std;
int bucket[1005]={0};
inline int read()
{
	int x=0;
	int y=1;
	char ch=getchar();
	while (ch<'0'||ch>'9')
	{
		if (ch=='-')
		{
			y=-1;
		}
		ch=getchar();
	}
	while (ch>='0'&&ch<='9')
	{
		x=x*10+ch-'0';
		ch=getchar();
	}
	return x*y;
}
inline void write(int x)
{
    if(x<0){
    	putchar('-');
		x=-x;
	}
    if(x>9) 
		write(x/10);
    putchar(x%10+'0');
}
inline void read_(int arr[],int n,int &sum)
{
    for (int i=1;i<=n;i++)
	{
	 	arr[i]=read();
	 	if (bucket[arr[i]])
	 	{
			continue;
		}
		bucket[arr[i]]++;
		sum++;
	}
}
int main()
{
	int n,a[105]={0},num=0;
	n=read();
	read_(a,n,num);
	write(num);
	putchar('\n');
	for (int i=1;i<=1005;i++)
	{
		if (bucket[i])
		{
			write(i);
			putchar(' ');
		}
	}
	return 0;
}