#include<bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;

int main() {
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    n++;
    vector<pll> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i].first;
        a[i].second = i;
    }
    sort(a.begin(), a.end());
    ll ans = 0;
    for (int i = 0; i < n; i++) {
        ll cur = abs(i - a[i].second);
        if (a[i].second < i) {
            cur += (a[i].second % 2);
        } else {
            cur += (a[i].second % 2 == 0);
        }
        ans = max(ans, cur);
    }
    cout << ans << endl;


}