#include <bits/stdc++.h>
#define pb push_back
#define endl ("\n")
#define all(aa) aa.begin(), aa.end()
typedef long long ll;
using namespace std;
struct SegmentTree{
int n;
vector<int> t;
SegmentTree(int n) : n(n), t(4 * n){}
void upd(int u, int tl, int tr, int pos, int val){
if(tl == tr){
t[u] = val;
return;
}
int tm = (tl + tr) / 2;
if(pos <= tm)
upd(u * 2, tl, tm, pos, val);
else
upd(u * 2 + 1, tm + 1, tr, pos, val);
t[u] = t[u * 2] + t[u * 2 + 1];
}
void upd(int pos, int val){
upd(1, 0, n - 1, pos, val);
}
int query(int u, int tl, int tr, int ql, int qr){
if(ql <= tl && tr <= qr){
return t[u];
}
int tm = (tl + tr) / 2;
int ret = 0;
if(ql <= tm)
ret += query(u * 2, tl, tm, ql, qr);
if(tm < qr)
ret += query(u * 2 + 1, tm + 1, tr, ql, qr);
return ret;
}
int query(int ql, int qr){
return query(1, 0, n - 1, ql, qr);
}
};
int main(){
int n;
cin >> n;
vector<int> a(n);
for(int i = 0; i < n; i++) cin >> a[i], a[i]--;
vector<int> pos(n);
for(int i = 0; i < n; i++) pos[a[i]] = i;
vector<vector<int>> inv(n, vector<int>(n));
for(int r = n - 1; r >= 0; r--){
SegmentTree st(n);
int cur = 0;
for(int l = r; l >= 0; l--){
cur += st.query(pos[l], n - 1);
inv[l][r] = cur;
st.upd(pos[l], 1);
}
}
vector<vector<int>> cros(n + 1, vector<int>(n + 1));
for(int l = 0; l <= n; l++){
SegmentTree st(n);
for(int i = 1; i <= l; i++){
st.upd(pos[i - 1], 1);
}
int cur = 0;
for(int r = l + 1; r <= n; r++){
cur += st.query(pos[r - 1], n - 1);
cros[l][r] = cur;
}
}
vector<int> dp(n + 1);
for(int k = 1; k <= n; k++){
dp[k] = INT_MAX;
for(int j = 0; j < k; j++){
dp[k] = min(dp[k], dp[j] + inv[j][k - 1] + cros[j][k]);
}
}
cout << dp[n] << endl;
}
