#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N = 4e5 + 10;

int n;
LL a[N], s[N];
LL ans = -1e18;

int main() {
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    a[n + i] = a[i];
  }

  for (int i = 1; i <= 2 * n; i++)
    s[i] = s[i - 1] + a[i];

  // 对于每个位置i，枚举它前面n个位置，找最小前缀和
  for (int i = 1; i <= 2 * n; i++) {
    LL minPrefix = s[i - 1]; // 初始化为i-1位置的前缀和
    for (int j = max(0, i - n); j <= i - 2; j++)
      minPrefix = min(minPrefix, s[j]);
    ans = max(ans, s[i] - minPrefix);
  }

  printf("%lld\n", ans);
  return 0;
}