#include <fstream>
#include <vector>
#include <algorithm>

using namespace std;

const char InFile[]="subsir2.in";
const char OutFile[]="subsir2.out";
const int MaxN=5010;

ifstream fin(InFile);
ofstream fout(OutFile);

int v[MaxN],best[MaxN],p[MaxN],n,sol,soli;
vector<int> ind;
vector<int> ind1,ind2;

int main()
{
	best[0]=0;
	fin>>n;
	for(register int i=1;i<=n;++i)
	{
		fin>>v[i];
		for(register int j=0;j<i;++j)
		{
			if(v[j]<v[i])
			{
				if(best[i]<best[j])
				{
					best[i]=best[j];
				}
			}
		}
		++best[i];
	}
	fin.close();
	
	sol=0;
	for(register int i=0;i<=n;++i)
	{
		if(best[i]>sol)
		{
			sol=best[i];
		}
	}
	
	fout<<sol<<"\n";
	fout.close();
	return 0;
}