#include<iostream>
#include<fstream>

using namespace std;
int p[5000],pp[5000];
int main()
{ifstream f("subsir2.in");
ofstream h("subsir2.out");
int n,i,a[5000],d[5000],j;
int A,inf=0x3f3f3f3f;
int min=inf;
f>>n;
f>>a[1];
d[1]=1;
for(i=2;i<=n;i++)
{f>>a[i];
A=inf;
for(j=i-1;j>=1;j--)
{if(d[j]+1>d[i]&&a[i]>=a[j])
{d[i]=d[j]+1;
A=a[j];
p[i]=j;
pp[j]=i;}
else
if(d[j]+1==d[i]&&a[i]>=a[j]&&a[j]<A)
{d[i]=d[j]+1;
A=a[j];
p[i]=j;
pp[j]=i;}
else
if(d[j]+1==d[i]&&a[i]>=a[j])
pp[j]=i;}



}




for(i=1;i<=n;i++)
	if(d[i]<min&&pp[i]==0)
		min=d[i];
	//cout<<pp[i]<<" ";
h<<min;	
	return 0;}