#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define MAXN (1000005)
int main() {
ios_base::sync_with_stdio(false);cin.tie(0);
ll N;
cin>>N;
ll H[N];
for(ll i = 0;i < N;i++){
cin>>H[i];
}
ll dp[N][1ll<<N];
for(ll i = 0;i < N;i++){
for(ll j = 0;j < (1ll<<N);j++){
dp[i][j] = 1e18;
}
}
for(ll i = 0;i < N;i++){
for(ll j = 0;j < (1ll<<N);j++){
ll on = 0;
for(ll bit = 0;bit < N;bit++){
if(j & (1ll<<bit)){
on++;
}
}
if(on != i + 1) continue;
if(i == 0){
ll first = 0;
for(ll bit = 0;bit < N;bit++){
if(j & (1ll<<bit)){
first = bit;
}
}
dp[i][j] = first;
continue;
}
for(ll bit = 0;bit < N;bit++){
if(j & (1ll<<bit)){
ll minus = 0;
for(ll b = 0;b < bit;b++){
if(j & (1ll<<b)){
minus++;
}
}
ll right = 0;
for(ll b = bit + 1;b < N;b++){
if(j & (1ll<<b)){
right++;
}
}
if(bit + right <= i) dp[i][j] = min(dp[i][j],dp[i - 1][j ^ (1ll<<bit)]);
else dp[i][j] = min(dp[i][j],dp[i - 1][j ^ (1ll<<bit)] + (bit + right - i) - minus);
}
}
}
}
cout<<dp[N - 1][(1ll<<N) - 1]<<'\n';
}
