A10

#include <set>
#include <iostream>

using namespace std;

int main() {
    int n;
    cin >> n;

    set<int> s;


    for (int i = 0; i < n; i++) {
        int x;
        cin >> x;
        s.insert(x);
    }
    cout << s.size()<<endl;

    for (int x : s) {
        cout << x << ' ';
    }


    s.erase(3);
    cout << endl;
    for (int x : s) {
        cout << x << ' ';
    }





}