//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <class T>
using Tree =
tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define int long long
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define rep(i, a, b) for (int i = a; i <= b; ++i)
#define per(i, b, a) for (int i = b; i >= a; --i)
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(), (v).end()
#define lsb(x) (x)&(-x)
#define bug(x) cerr << #x << " " << x << endl;
void setIO(string name = "") {
ios_base::sync_with_stdio(false);
cin.tie(nullptr); cout.tie(nullptr);
if (!name.empty()) {
freopen((name + ".in").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
}
}
ll fexp(ll a, ll b, ll m) {
if (b == 0) return 1LL;
ll p = a;
ll ans = 1;
while (b > 0) {
if (b % 2 != 0) ans = (ans * p) % m;
p = (p * p) % m;
b >>= 1;
}
return ans;
}
const int MAXN = 5e3 + 10;
const int INF = 1e18 + 5;
const int MOD = 1e9+7;
int a[MAXN], dp[MAXN], inv[MAXN], bit[MAXN],n;
void update(int i, int x) {
for (;i <= n; i += lsb(i)) bit[i] += x;
}
int query(int i) {
int ans = 0;
for (; i > 0; i -= lsb(i)) ans += bit[i];
return ans;
}
void solve() {
cin >> n;
rep(i,1,n) {
cin >> a[i];
inv[a[i]] = i;
update(i,1);
}
rep(i,1,n) {
update(i,-1);
dp[i] = INF;
per(j,i,1) {
update(j,1);
int x = 0;
rep(k,j,i) {
update(k,-1);
x += query(inv[k]);
}
rep(k,j,i) update(k,1);
dp[i] = min(dp[i], dp[j-1] + x);
}
per(j,i,1) update(j,-1);
}
cout << dp[n] << '\n';
}
int32_t main() {
setIO();
int tt = 1;
//cin >> tt;
while (tt-- > 0) solve();
return 0;
}
