#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main() {
#ifdef ONPC
freopen("input.txt", "r", stdin);
#else
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#endif // ONPC
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++) {
cin >> a[i];
}
if (n <= 13) {
function<bool(vector<int>)> isgood = [&](vector<int> perm) {
bool ok = true;
for (int l = 0; l < n; l++) {
int mn = n + 1, mx = 0;
for (int r = l; r < n; r++) {
mx = max(mx, perm[r]);
mn = min(mn, perm[r]);
if (mn != perm[l] && mn != perm[r] && mx != perm[l] && mx != perm[r]) {
ok = false;
}
}
}
return ok;
};
int sol = (int) 1e9;
vector<bool> vis(n + 1, 0);
vector<int> perm;
function<void(int)> bkt = [&] (int pos) {
if (pos == n + 1) {
if (isgood(perm)) {
int cost = 0;
for (int i = 0; i < n; i++) {
cost += (perm[i] != a[i]);
}
sol = min(sol, cost);
}
}
for (int i = 1; i <= n; i++) {
if (!vis[i]) {
vis[i] = 1;
perm.push_back(i);
int mn = perm.back(), mx = perm.back();
bool ok = true;
for (int l = pos - 1; l >= 0; l--) {
mx = max(mx, perm[l]);
mn = min(mn, perm[l]);
if (mn != perm[l] && mx != perm[l] && mn != perm.back() && mx != perm.back()) {
ok = false;
break;
}
}
if (ok) bkt(pos + 1);
perm.pop_back();
vis[i] = 0;
}
}
};
bkt(1);
cout << sol << "\n";
return 0;
}
return 0;
}
