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

const int N = 2e5 + 10, INF = 1E9 + 10;
int n;
int a[N];
long long k[N];
int main()
{
	cin >> n;
	for (int i = 1; i <= n; i ++)
	{
		cin >> a[i];
		k[i] = a[i] + k[i - 1];
	}
	long long cnt = INF;
	for(int i = 1; i <= n; i ++)
	{
		if (a[i] < 0)
		{
			long long p = a[i];
			int j = 0;
			for (j = i + 1; p < 0 && j <= n; j ++)
			{
				cnt = min(cnt, p);
				p += a[j];
			}
			i += (j - i) - 1;
		}
	}
	long long ans2 = -INF;
	for(int i = 1; i <= n; i ++)
	{
		if (a[i] > 0)
		{
			long long p = a[i];
			int j;
			for (j = i + 1; p > 0 && j <= n; j ++)
			{
				ans2 = max(ans2, p);
				p += a[j];
			}
			i += (j - i) - 1;
		}
	}
	long long ans;
	ans = k[n] - cnt;
	ans = max(ans2, ans);
	cout << ans << "\n ";
	return 0;
}