#include <fstream>
using namespace std;
ifstream fin("subsir2.in");
ofstream fout("subsir2.out");
const int inf=1000001;
int v[5001],s[5001],l[5001],ind[5001],last,j,ld,ls,n,m,i;
int main ()
{
    fin>>n;
    for (i=1;i<=n;i++)
    {
        fin>>v[i];
        if (v[i]>s[last]) {s[++last]=v[i]; ls=last;}
        else
        {
            ls=1;
            ld=last;
            while (ls<ld)
            {
                m=(ls+ld)/2;
                if (v[i]<=s[m]) ld=m-1;
                else ls=m+1;
            }
            if (s[ls]>=v[i]) s[ls]=v[i];
            else {ls++; s[ls]=v[i];}
        }
        l[i]=ls;
    }
    fout<<last<<"\n";
	for (i=1;i<=last;i++) v[i]=inf; 
    j=last;
    for (i=n;i>0;i--)
    {
        if (v[l[i]]>s[i]) {v[l[i]]=s[i]; ind[l[i]]=i;}
    }
    for (j=1;j<=last;j++) fout<<ind[j]<<" ";
}