#include<bits/stdc++.h>
using namespace std;
int const maxn = 105;
int N,nums[maxn],ans[maxn];
int main(){
	cin>>N;
	for(int i = 1;i <= N;i++){
		cin>>nums[i];
	}
	sort(nums,nums+N);
	int now = 0,count = 1;
	for(int i = 1;i <= N;i++){
		if(nums[i] == now){
			continue;
		}
		else{
			now = nums[i];
			ans[count] = now;
			count++;
		}
	}
	sort(ans,ans+N);
	cout<<count-1<<endl;
	cout<<ans[2];
	for(int i = 3;i <= count;i++){
		cout<<" "<<ans[i];
	}
	cout<<endl; 
	return 0;
}