// IamHereForFun //
#include <bits/stdc++.h>
using namespace std;
#define LSOne(X) ((X) & -(X))
const int N = 5e3 + 5;
const int M = 2e5 + 5;
const int L = 12;
const int LG = 25;
const int P = 37;
const long long INF = 1e18 + 5;
const int MOD = 1e9 + 7;
const int nx[] = {0, -1, 0, 1}, ny[] = {-1, 0, 1, 0};
// dp[i] = minimum swap to fix the first i number.
// so we can't calculate the sum of positions to find it .-.z
// val[i] is the number of number that is smaller than i and appears after i
// we see that every time we push a number to the front, we can reduce some swap from the numbers that is smaller than it that has been swapped(basically the pos and val thingy)
int n, a[N], dp[N], val[N], pos[N];
void solve()
{
cin >> n;
for (int x = 1; x <= n; x++)
{
cin >> a[x];
dp[x] = 1e9;
}
for (int x = 1; x <= n; x++)
{
for (int y = x; y <= n; y++)
{
if (a[y] < a[x])
val[a[x]]++;
}
}
dp[0] = 0;
for (int x = 0; x < n; x++)
{
int cur = 0, id = 0;
for(int y = 1; y <= n; y++)
{
if(a[y] > x)
{
pos[a[y]] = id;
id++;
}
}
for (int y = x + 1; y <= n; y++)
{
cur -= val[y];
cur += pos[y];
dp[y] = min(dp[y], dp[x] + cur);
// cout << cur << " ";
}
// cout << "\n";
// cout << dp[x] << " " << x << "\n";
for (int y = 1; y <= n; y++)
{
if (a[y] == x + 1)
break;
if (a[y] > x + 1)
val[a[y]]--;
}
}
cout << dp[n];
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
for (int x = 1; x <= t; x++)
{
solve();
}
return 0;
}
