#include <algorithm>
#include <iostream>
using namespace std;
const int N = 5000;
int aa[N], ii[N], kk[N][N], xx[N][N], dp[N];
int main() {
ios_base::sync_with_stdio(false), cin.tie(NULL);
int n; cin >> n;
for (int i = 0; i < n; i++)
cin >> aa[i], ii[--aa[i]] = i;
for (int a = 0; a < n; a++) {
if (a)
for (int i = 0; i < n; i++)
kk[a][i] = kk[a - 1][i];
for (int i = ii[a]; i < n; i++)
kk[a][i]++;
}
for (int l = 0; l < n; l++)
for (int k = 0, r = l; r < n; r++) {
k += l;
if (r)
k += kk[r - 1][ii[r]];
if (l)
k -= kk[l - 1][ii[r]] * 2;
xx[l][r] = k;
}
for (int i = 0; i < n; i++) {
dp[i] = xx[0][i];
for (int j = 0; j < i; j++)
dp[i] = min(dp[i], dp[j] + xx[j + 1][i]);
}
cout << dp[n - 1] << '\n';
return 0;
}
