#include<stdio.h>

#define dim 5000

int a[dim],b[dim],c[dim];
int n,i,k;
    
void solve()
{
     int nr,min,poz;
     scanf("%d",&n);
     for(i=1;i<=n;i++)
     {
                      scanf("%d",&a[i]);
                      nr=0;
                      min=1000;
                      for(k=1;k<=i;k++)
                      {
                                       if(a[k]<=a[i] && a[k]<=min || b[k]>=nr && a[k]<=a[i])
                                       nr=b[k],min=a[k], poz=k;
                                       }
                      b[i]=nr+1;
                      c[i]=poz;
                   //   printf("%d ",c[i]);
                      }
     min=0;
     poz=1;
     for(i=1;i<=n;i++)
     if(min<b[i])
     min=b[i];
     printf("%d\n",min);
                     
return ;
}    
int main ()
{
    freopen ("subsir2.in","r",stdin);
    freopen ("subsir2.out","w",stdout);
    solve();
    return 0;
}