a=int(input())
b=[int(i) for i in input().split()]
c=[]
d=a-1
for i in range(a):
if b.count(b[d])==1:
c=c+[b[d]]
if b.count(b[d])!=1 and c.count(b[d])==0:
c=c+[b[d]]
d=d-1
c=c[::-1]
print(len(c))
print(*c)
#include <bits/stdc++.h>
using namespace std;
int was[1005];
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n;
cin >> n;
int a[n+3];
vector <int> v;
for(int i=1;i<=n;i++){
cin >> a[i];
}
for(int i=n;i>=1;i--){
if(was[a[i]]==0){
v.push_back(a[i]);
was[a[i]]++;
}
}
reverse(v.begin(),v.end());
cout << v.size() << "\n";
for(int i=0;i<v.size();i++){
cout << v[i] << " ";
}
return 0;
}489A - SwapSort | 932A - Palindromic Supersequence |
433A - Kitahara Haruki's Gift | 672A - Summer Camp |
1277A - Happy Birthday Polycarp | 577A - Multiplication Table |
817C - Really Big Numbers | 1355A - Sequence with Digits |
977B - Two-gram | 993A - Two Squares |
1659D - Reverse Sort Sum | 1659A - Red Versus Blue |
1659B - Bit Flipping | 1480B - The Great Hero |
1519B - The Cake Is a Lie | 1659C - Line Empire |
515A - Drazil and Date | 1084B - Kvass and the Fair Nut |
1101A - Minimum Integer | 985D - Sand Fortress |
1279A - New Year Garland | 1279B - Verse For Santa |
202A - LLPS | 978A - Remove Duplicates |
1304A - Two Rabbits | 225A - Dice Tower |
1660D - Maximum Product Strikes Back | 1513A - Array and Peaks |
1251B - Binary Palindromes | 768B - Code For 1 |