#include <bits/stdc++.h> using namespace std; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); int n; cin >> n; vector<int> a(n); for (auto &x : a) cin >> x; vector<int> pos(n + 1); for (int i = 0; i < n; i++) pos[a[i]] = i; vector<int> b = a; sort(b.begin(), b.end()); long long ans = LLONG_MAX; do { bool ok = true; for (int i = 0; i + 1 < n; i++) { if (!(b[i] < b[i + 1] + 2)) { ok = false; break; } } if (!ok) continue; vector<int> m(n); for (int i = 0; i < n; i++) m[i] = pos[b[i]]; long long e = 0; for (int i = 0; i < n; i++) { for (int j = i + 1; j < n; j++) { if (m[i] > m[j]) e++; } } ans = min(ans, e); } while (next_permutation(b.begin(), b.end())); cout << ans; }