#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1000000007;
using P = pair<int,int>;
#define rep(i, n) for(int i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()

int main(){
    ll n;
    cin >> n;
    vector<ll> p(n), pinv(n);
    rep(i,n){
        cin >> p[i]; p[i]--;
        pinv[p[i]] = i;
    }
    ll ans = 0;
    rep(i,n-1){
        ll nans = -2 * (pinv[n-1-i] + 1);
        nans += (n-i) * (n-i+1) / 2;
        ans = max(ans,nans);
    }
    cout << ans << endl;
    return 0;
}