#include <fstream>

using namespace std;

ifstream f("subsir2.in");
ofstream g("subsir2.out");

int n, i, lg;
int v[5001], m[5001], ant[5001];

int cb(int x, int dr)
{
    int st = 1, mij, poz = 0;
    while (st <= dr)
    {
        mij = (st + dr) / 2;
        if (v[m[mij]] < x)
        {
            poz = mij;
            st = mij + 1;
        }
        else
            dr = mij - 1;
    }
    return poz;
}

void afisare(int k)
{
    if (ant[k])
        afisare(ant[k]);
    g << k << " ";
}

int main()
{
    f >> n;
    for (i=1; i<=n; i++)
    {
        f >> v[i];
        int p = cb(v[i], lg);
        if (p == lg)
            lg++;
        if (v[m[p+1]] != v[i])
        {
            m[p+1] = i;
            ant[i] = m[p];
        }
    }

    g << lg << "\n";
    afisare(m[lg]);

    return 0;
}