#include <bits/stdc++.h>
using namespace std;

int main()
{
	int N;
	cin >> N;
	vector<int> a( N );
	for( int i = 0; i < N; i++ ) cin >> a[i];

	typedef pair<int, int> P;
	vector<P> p( N );
	for( int i = 0; i < N; i++ ) p[i] = P( a[i], i + 1 );
	sort( p.begin(), p.end() );
	vector<long long> acc( N + 1 );
	for( int i = 0; i < N; i++ ) {
		acc[i + 1] = acc[i] + p[i].second;
	}
	long long ans = 0;
	for( int i = N - 1; i >= 0; i-- ) {
		long long a = -p[i].second;
		if( i - 1 >= 0 ) a += acc[i]; 
		ans = max( ans, max( a, 0LL ) );
	}

	cout << ans << endl;
}