#include <bits/stdc++.h>
using namespace std;
#define st first
#define nd second
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef long double ld;
const int maxn = 5009;
int dp[maxn];
int inw[maxn][maxn];
int C[maxn][maxn];
bool czyinw[maxn][maxn];
int a[maxn];
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int N;
cin >> N;
for(int i = 1; i <= N ; i++)cin >> a[i];
for(int i = 1; i <= N; i++)
{
for(int j = 1 ; j < i; j++)
{
if(a[i] < a[j])
{
czyinw[a[i]][a[j]] = 1;
czyinw[a[j]][a[i]] = 1;
}
}
}
dp[0] = 0;
for(int i = 1 ; i <= N ; i++)
{
dp[i] = i*i;
inw[i][i] =0 ;
for(int j = i-1 ; j >= 1 ; j--)
{
inw[i][j] = inw[i][j+1];
if(czyinw[j][i])inw[i][j]++;
}
for(int j = 1 ; j <= i ; j++)inw[i][j] += inw[i-1][j];
C[i][i] = 0;
for(int j = i-1 ; j >= 1 ; j--)
{
C[i][j] = 0;
if(czyinw[j][i])
{
C[i][j+1] += 1;
}
}
for(int j = 1 ; j <= i ; j++)
{
C[i][j] = C[i][j-1] + C[i][j];
}
for(int j = 1; j <= i ;j++)C[i][j] += C[i-1][j];
for(int j = 0 ; j < i ; j++)
{
dp[i] = min(dp[i] , dp[j] + min(inw[i][j+1], (i-j)*(i-j-1)/2 - inw[i][j+1]) + C[i][j+1]);
}
}
cout << dp[N] << '\n';
return 0;
}
