#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <queue>
using namespace std;
int n;
vector<int>a, idx;
vector<int>p;
int const inf = 1e9;
vector<int>dp;
vector<vector<int>>dpcost;
int cost(int pos, int val){
if(dpcost[pos][val] != -1)
return dpcost[pos][val];
//cout << "cost(" << pos << ',' << val << ")\n";
iota(p.begin(), p.end(), 0);
reverse(p.begin()+pos, p.begin()+val+1);
int inv = 0;
for(int i = pos; i <= val; i++){
for(int j = i+1; j <= n; j++){
if((p[i] < p[j] && idx[i] > idx[j]) ||
(p[i] > p[j] && idx[i] < idx[j]))
inv++;
}
}
return dpcost[pos][val] = inv;
}
int solve(int k){
if(k > n)
return 0;
if(dp[k] != -1)
return dp[k];
//cout << "solve(" << k <<")" << endl;
if(k > n)
return 0;
int ans = inf;
for(int i = k; i <= n; i++){
ans = min(ans, cost(k, i) + solve(i+1));
}
return dp[k] = ans;
}
int main(){
cin >> n;
a.resize(n+1);
p.resize(n+1);
idx.resize(n+1);
dp.resize(n+1, -1);
dpcost.resize(n+1, vector<int>(n+1, -1));
for(int i = 1; i <= n; i++){
cin >> a[i];
idx[a[i]] = i;
}
cout << solve(1) << '\n';
return 0;
}
