#include <bits/stdc++.h>
#define ii pair<int, int>
#define fi first
#define se second
#define siz(v) ((int)(v).size())
#define all(v) begin((v)), end(v)
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(i) (1LL << (i))
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define dbg(x) "[" #x " = " << x << "]"
#define lli pair<long long, int>
#define left __left
#define right __right
using namespace std;
bool M1;
const int MAXN = 5005, MAXK = 16, LOG = 20, infINT = 1e9 + 23737;
const long long inf = 1e18;
const int dx[4] = {-1, 0, 0, 1};
const int dy[4] = {0, -1, 1, 0};
template<class X, class Y> bool minimize(X &x, const Y &y){return x > y ? x = y, 1: 0;}
template<class X, class Y> bool maximize(X &x, const Y &y){return x < y ? x = y, 1: 0;}
int numVal, val[MAXN], pos[MAXN];
void input(){
cin >> numVal;
for(int i = 0; i < numVal; i++) cin >> val[i], pos[val[i]] = i;
}
namespace sub2{
bool checkSub(){
return 1;
}
int dp[MASK(21) + 1][22];
string binary(const int &mask){
string s = "";
for(int i = 0; i < numVal; i++) s += (BIT(mask, i) + '0');
return s;
}
void solve(){
memset(dp, 0x3f, sizeof dp);
for(int i = 0; i < numVal; i++) dp[MASK(i)][val[i]] = i;
for(int mask = 1; mask < MASK(numVal); mask++){
int cur = __builtin_popcount(mask);
for(int j = 1; j <= numVal; j++) if (!BIT(mask, pos[j])){
int ncur = pos[j];
for(int k = pos[j] + 1; k < numVal; k++) if (BIT(mask, k)) ncur++;
for(int i = 1; i <= j + 1; i++) if (dp[mask][i] < infINT){
minimize(dp[mask | MASK(pos[j])][j], dp[mask][i] + (ncur - cur));
}
}
}
int best = infINT;
for(int i = 1; i <= numVal; i++) minimize(best, dp[MASK(numVal) - 1][i]);
cout << best << '\n';
}
}
bool M2;
signed main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define task "test"
if (fopen(task".inp", "r")){
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int t = 1;
// cin >> t;
while(t--){
input();
if (sub2::checkSub()) sub2::solve();
}
cerr << TIME << ".s\n";
cerr << (&M2 - &M1) / 1048576 << " MB\n";
}
