#include <bits/stdc++.h>
#define N 5000

using namespace std;

ifstream fin("subsir2.in");
ofstream fout("subsir2.out");

int n, m, q, a[N+2], t[N+2], pre[N+2], sol[N+2];

int bs(int val)
{
    int st=1, dr=m, mijl;
    while(st<=dr)
    {
        mijl=st+(dr-st)/2;
        if(val>=a[t[mijl]]) st=mijl+1;
        else dr=mijl-1;
    }
    return st;
}

int main()
{
    int i, k;
    fin>>n;
    for(i=1; i<=n; i++) fin>>a[i];
    t[1]=1, m=1;
    for(i=2; i<=n; i++)
    {
        k=bs(a[i]);
        t[k]=i;
        pre[i]=t[k-1];
        m=max(m,k);
    }
    fout<<m<<'\n';
    for(i=t[m]; i>0; i=pre[i]) sol[++q]=i;
    for(i=q; i>=1; i--) fout<<sol[i]<<' ';
    return 0;
}