#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
#define pb push_back
#define pii pair<ll, ll>
#define pll pair<ll, ll>
#define st first
#define nd second
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
#define debug false
const int MAXN = 5000;
int a[MAXN + 1];
int dp[MAXN + 1];
int pos[MAXN + 1];
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];
pos[a[i]] = i;
}
for (int i = 1; i <= n; i ++) {
dp[i] = INT_MAX;
}
dp[0] = 0;
for (int i = 1; i <= n; i ++) {
for (int j = 0; j < i; j ++) {
int cnt = 0;
for (int k = j + 1; k <= i; k ++) {
for (int l = j + 1; l < k; l ++) {
cnt += (pos[k] > pos[l]);
}
}
//cout << cnt << "\n";
for (int k = 1; k <= j; k ++) {
for (int l = j + 1; l <= i; l ++) {
cnt += (pos[k] > pos[l]);
}
}
dp[i] = min(dp[i], dp[j] + cnt);
//cout << cnt << "\n";
}
}
cout << dp[n] << "\n";
return 0;
}
