#include <iostream>
using namespace std;
long int m, now, n, p, i, ch;
int main(void)
{
	cin >> n;//입력 받을 수는 n개
	for (i = 0; i < n; i++)
	{
		cin >> p;//i+1번째 수를 입력받음
		if (i == 0)//첫 수일 경우
		{
			m = p;//최댓값은 p
			now = p;//현재 합 값도 p
            continue;
		}
		if (ch == 1 && p + now > 0)//한 번이라도 양수가 나온 적이 있으며, 현재 수를 더했을 때 양수가 된다면
			now += p;//현재 합 값은 p를 추가한 값
		else
		{
			now = p;//이외에는 p를 현재 합 값으로
			if (ch == 0 && now > 0)
				ch = 1;//현재 합이 0 이상이라는 것은 양수가 한 번이라도 나왔다는 뜻. ch가 0이면 나온 적이 없다는 뜻
		}
		m = (m > now ? m : now) > p ? (m > now ? m : now) : p;//이전 now 값이 음수여서 p 값이 현 최댓값일 수 있음.
	}
	cout << m << endl;//최댓값 출력
	return 0;
}

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