#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef __int128 lll;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pld;
#define MAX 9223372036854775807LL
#define MIN -9223372036854775807LL
#define INF 0x3f3f3f3f3f3f3f3f
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); cout << fixed; cout.precision(10);
#define sp << " "
#define en << "\n"
#define compress(v) sort(v.begin(), v.end()), v.erase(unique(v.begin(), v.end()), v.end())
ll n;
ll a[5010];
ll dp[5010];
ll w[5010];
struct fenwicktree
{
ll bit[5010];
void init(void)
{
for(ll i = 0 ; i <= n ; i++)
bit[i] = 0;
}
void update(ll W, ll v)
{
if(W == 0)
return;
for(ll i = W ; i <= n ; i += (i & (-i)))
bit[i] += v;
}
ll query(ll W)
{
ll ret = 0;
for(ll i = W ; i > 0 ; i -= (i & (-i)))
ret += bit[i];
return ret;
}
}BIT, BIT2;
int main(void)
{
fastio
cin >> n;
for(ll i = 1 ; i <= n ; i++)
{
cin >> a[i];
w[a[i]] = i;
dp[i] = INF;
}
dp[0] = 0;
for(ll i = 1 ; i <= n ; i++)
{
BIT.init();
BIT2.init();
for(ll j = 1 ; j < i ; j++)
BIT.update(w[j], 1);
ll sum = 0;
for(ll j = i - 1 ; j >= 0 ; j--)
{
ll now = w[j + 1] + BIT.query(n) - BIT.query(w[j + 1] - 1);
sum += now;
dp[i] = min(dp[i], dp[j] + sum - (i + j + 1) * (i - j) / 2);
BIT.update(w[j + 1], 1);
BIT2.update(w[j + 1], 1);
BIT.update(w[j], -1);
sum -= BIT2.query(w[j]);
}
}
cout << dp[n];
return 0;
}
