#include <bits/stdc++.h>

using namespace std;

set <int> S;
int N;

int main()
{
    ifstream in("scmax.in");
    ofstream out("scmax.out");

    in >> N;

    for ( int i = 0, a; i < N; i++ )
    {
        in >> a;

        S.insert( a );
        auto it = ++S.find( a );

        if ( it != S.end() )
            S.erase( it );
    }

    out << S.size() << "\n";

    for ( auto x: S )
        out << x << " ";
}