#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define int long long
#define pii pair<int,int>
#define vi vector<int>
#define ff first
#define ss second
#define sp << " " <<
#define all(x) x.begin(),x.end()
#define big(x) ((int)(x.size()))
using namespace std;
const int MOD = 1e9+7, LIM = 1e6+1, inf = 2e18;
const int N = 2e5+1;
struct FT {
vi bit;
int n;
FT(int nn) {
n = nn;
bit.assign(n + 1, 0);
}
void put(int p, int v) {
for (int i = p; i <= n; i += i & -i) bit[i] += v;
}
int get(int p) {
int ans = 0;
for (int i = p; i > 0; i -= i & -i) ans += bit[i];
return ans;
}
int get(int l, int r) {
return get(r) - get(l - 1);
}
void reset() {
bit.assign(n+1,0);
}
};
void solve() {
int n;
cin >> n;
vi a(n+1),pos(n+1);
for (int i=1;i<=n;i++) cin >> a[i];
for (int i=1;i<=n;i++) pos[a[i]] = i;
vi dp(n+1,inf);
dp[0] = 0;
vi pref(n+1,0);
FT ft(n);
for (int i=0;i<n;i++) {
//ilk i yere i sayıyı yerleştirdim
int cost = 0;
pref.assign(n+1,0);
for (int j = 1;j<=n;j++) pref[j] = pref[j-1]+(a[j] > i);
ft.reset();
for (int j = i+1;j<=n;j++) {
//[i+1..j] gelcek şimdi
cost-=ft.get(pos[j]+1,n);
cost+=pref[pos[j]-1];
dp[j] = min(dp[j],dp[i]+cost);
ft.put(pos[j],1);
}
}
cout << dp[n] << '\n';
}
signed main() {
ios_base::sync_with_stdio(0); cin.tie(0);
#ifdef Dodi
freopen("in.txt", "r", stdin);
freopen("out.txt", "w", stdout);
#endif
int t = 1;
//cin >> t;
while (t --> 0) solve();
}
