#include <iostream>
#include <algorithm>
#include <cstdio>
#include <vector>
#include <cstring>

using namespace std;

vector<int> v;
int n;

int main(){
    cin >> n;
    for ( int i = 0; i < n; i ++ ){
        int x; scanf("%d", &x);
        v.push_back(x);
    }
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());
    printf("%d\n", v.size());
    for ( auto i : v ) printf("%d ", i);
    return 0;
}

n = int(input())
c = input()
a = []
l = c.split(' ')
for i in range(0,len(l)):
a.append(int(l[i]))
a = list(set(a))
a.sort()

print(len(a))

for i in range(len(a)):
print(a[i],end=' ')

n=input()
s=set()
p=input().split()
l=list(set(p))
#按照数据大小排序
l.sort(key=int)
print(len(l))
for i in l :
print(i,end=" ")

n=int(input())
s=[0 for i in range(0,1005)]
a=input().split()
ans=n

for i in range(0,n):
    if s[int(a[i])]==1:
        ans-=1;
    s[int(a[i])]=1
    
    
print(ans)
for i in range(1,1001):
    if s[i]==1:
        print(i,end=" ")

a = int(input())
data = []
b = input()
array = b.split(" ")
def redun(x):
for i in range(len(data)):
if data[i] == x:
return True
return False

for i in range(a):
t = array[i]
if redun(t)==False:
data.append(t)
another = []
for i in range(len(data)):
another.append(int(data[i]))
print(len(another))
another.sort()
for i in range(len(data)):
print(another[i],end=" ")