#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
using namespace std;
#define int long long
#define nl '\n'
#define io ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
mt19937 rng((unsigned)chrono::steady_clock::now().time_since_epoch().count());
const int mod = 1000000007, mod2 = 998244353;
// change this
const int N = 5005;
int n, h[N], fw[N], fw2[N], pos[N], dp[N];
void update(int x, int v) {
for (; x<N; x+=x&(-x)) fw[x] += v;
}
int sum(int x) {
int res = 0;
for(; x; x-=x&(-x)) res += fw[x];
return res;
}
void update2(int x, int v) {
for (; x<N; x+=x&(-x)) fw2[x] += v;
}
int sum2(int x) {
int res = 0;
for(; x; x-=x&(-x)) res += fw2[x];
return res;
}
signed main() {
io;
cin >> n;
for (int i=1; i<=n; i++) {
cin >> h[i];
pos[h[i]] = i;
}
for (int i=1; i<=n; i++) {
dp[i] = 1e18;
int ans = 0;
for (int j=1; j<=i; j++) {
ans += sum(pos[j] - 1);
update(pos[j], 1);
}
memset(fw2, 0, sizeof fw2);
for (int j=0; j<i; j++) {
// find dp
dp[i] = min(dp[i], dp[j] + ans);
// remove
ans -= sum(n) - sum(pos[j+1]);
ans -= sum2(n) - sum2(pos[j+1]);
update(pos[j+1], -1);
// add
ans += sum(pos[j+1]);
update2(pos[j+1], 1);
}
}
cout << dp[n] << nl;
}
