#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll N; cin >> N;
    vector<int> P(N + 1), A(N + 1);
    for(int i = 1; i <= N; i++) cin >> P[i], A[P[i]] = i;
    ll ans = -1e18, sum = N * (N + 1) / 2;
    for(int i = N; i >= 0; i--) {
        ans = max(ans, sum - A[i] - A[i]);
        sum -= A[i];
    }
    cout << ans << endl;
}