#include <vector>
#include <iostream>
#include <algorithm>
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];
	}
	vector<int> IP(N);
	for (int i = 0; i < N; ++i) {
		IP[P[i]] = i;
	}
	long long ans = 0, sum = 0;
	for (int i = 0; i < N; ++i) {
		if (i >= 1) {
			ans = max(ans, sum - (IP[i] + 1));
		}
		sum += IP[i] + 1;
	}
	cout << ans << endl;
	return 0;
}