#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<int> P(N);
  for (int i = 0; i < N; i++){
    cin >> P[i];
    P[i]--;
  }
  if (N == 1){
    cout << 0 << endl;
  } else {
    vector<int> A(N);
    for (int i = 0; i < N; i++){
      A[P[i]] = i + 1;
    }
    vector<long long> S(N + 1);
    S[0] = 0;
    for (int i = 0; i < N; i++){
      S[i + 1] = S[i] + A[i];
    }
    long long ans = 0;
    for (int i = 1; i < N; i++){
      ans = max(ans, S[i] - A[i]);
    }
    cout << ans << endl;
  }
}