#include <bits/stdc++.h>
using namespace std;
static const int INF = 1000000007;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
int N;
cin >> N;
vector<int> z(N), pos(N);
for (int i = 0; i < N; i++) {
cin >> z[i];
z[i]--;
}
for (int i = 0; i < N; i++) {
pos[z[i]] = i;
}
int pre[5005][5006];
for (int v = 0; v <= N; v++) {
pre[N - 1][v] = 0;
}
for (int p = N - 1; p > 0; p--) {
int val = z[p];
for (int v = 0; v <= val; v++) {
pre[p - 1][v] = pre[p][v] + 1;
}
for (int v = val + 1; v <= N; v++) {
pre[p - 1][v] = pre[p][v];
}
}
vector<int> dp(N + 1, INF);
dp[0] = 0;
for (int i = 1; i <= N; i++) {
long long tmp = 0;
for (int j = i - 1; j >= 0; j--) {
tmp += (N - i) + pre[pos[j]][j] - 2 * pre[pos[j]][i];
dp[i] = min(dp[i], dp[j] + (int)tmp);
}
}
cout << dp[N] << "\n";
return 0;
}
