#include <bits/stdc++.h>
using namespace std;
const int N=400;
bool dp[N][N],seen[N];
int a[N],valid[N];
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n;
cin>>n;
for(int i=1;i<=n;i++)
{
cin>>a[i];
valid[i]=i;
if(a[i-1]<=a[i])
{
valid[i]=valid[i-1];
}
}
dp[0][0]=1;
for(int i=1;i<=n;i++)
{
for(int j=1;j<=i;j++)
{
set<int> vis;
for(int ip=0;ip<i;ip++)
{
vis.insert(a[ip]); // 0 for ip=0 thus will not intersect any range
auto it=vis.upper_bound(a[ip+1]); // there can be elements equal to a[ip+1] but give no fk
if((1+ip)>=valid[i] and (it==end(vis) or *it>=a[i])) // >= or > ? idk
{
dp[i][j]|=dp[ip][j-1];
}
}
}
}
for(int j=1;j<=n;j++)
{
if(dp[n][j])
{
cout<<j<<endl;
return 0;
}
}
// cout<<endl;
}
