#include <bits/stdc++.h>
using namespace std;
int x,i,j,a,ans;
int q[100010];
int main(){
	cin>>x;
	for(i=0;i<x;i++){
		cin>>q[i];
    }
    ans=x;
    for(i=0;i<x;i++){
    	for(j=0;j<x;j++){
    		if(q[j]==q[i]){
    			q[j]=-1;
    			ans--;
			}
    		if(i==0) continue;
    		if(q[i]<q[i-1]){
			    a=q[i];
			    q[i]=q[i-1];
			    q[i-1]=a;
		    }
		} 
	}
	cout<<ans<<endl;
	for(i=0;i<x;i++){
		if(q[i]==-1) continue;
		cout<<q[i]<<' ';
    }
	return 0;
}