/**
____ ____ ____ ____ ____ ____
||l |||e |||i |||n |||a |||d ||
||__|||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|/__\|
**/
#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef long long ll;
void speed()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
const int maxn = 5010;
int n, a[maxn], dp[maxn], pos[maxn], fen[maxn];
void add(int pos, int val)
{
for (int i = pos; i <= n; i += (i & -i))
fen[i] += val;
}
int query(int pos)
{
int s = 0;
for (int i = pos; i > 0; i -= (i & -i))
s += fen[i];
return s;
}
void solve()
{
cin >> n;
for (int i = 1; i <= n; i ++)
{
cin >> a[i];
pos[a[i]] = i;
}
for (int i = 1; i <= n; i ++)
{
dp[i] = n * n;
for (int j = 0; j < i; j ++)
{
if (j > 0)
add(pos[j], 1);
int st = j + 1, sum = 0;
for (int k = i; k > j; k --)
{
ll cur = pos[k] + (j + (i - k) - query(pos[k] - 1));
///cout << i << " " << j << " " << k << " " << cur << endl;
add(pos[k], 1);
cur -= st;
st ++;
sum = sum + max((ll)0, cur);
}
for (int k = i; k > j; k --)
add(pos[k], - 1);
///cout << i << " " << j << " " << sum << endl;
dp[i] = min(dp[i], dp[j] + sum);
}
for (int j = 0; j < i; j ++)
if (j > 0)
add(pos[j], - 1);
///cout << i << " -- " << dp[i] << endl;
}
cout << dp[n] << endl;
}
int main()
{
solve();
return 0;
}
