#include<algorithm>

 #include<iostream>

 #include<cstdlib>

 #include<cstring>

 #include<cstdio>

 #include<cmath>

 #define N 5001

 using namespace std;

 int a[N],f[N],n,ans;

 int main()

 {

     int i=,j;

     scanf("%d",&n);

     for (i=;i<=n;i++) scanf("%d",&a[i]);

     for (i=;i<=n;i++)

     {

         for (j=;j<i;j++)

         {

             if (a[j]<a[i])

             {

                 if (f[i]<f[j]+)

                 {

                     f[i]=f[j]+;

                     ans=max(ans,f[i]);

                 }

             }

         }

     }

     printf("%d\n",ans);

     return ;

 }