10
-3 4 -4 1 1 -4 -5 3 -4 -2
 10
8 9 -10 -10 -4 -3 5 9 -9 9
 6
5 -4 2 -1 2 -2
 11
3 0 1 -2 5 -5 -1 0 3 2 2
 10
4 -2 -2 -2 2 0 1 0 -4 -1
 4
2 2 -3 4
 11
-11 -7 -2 -24 30 -26 24 9 -8 -9 23
 6
30 -29 5 5 -29 30
 24
-8 -6 6 -11 -15 -7 10 -19 -6 21 14 -4 -21 -10 12 17 1 -1 5 19 2 0 -4 -23
 10
-9 -6 -1 9 -2 0 0 -1 5 0
 6
10 -8 3 3 -8 10
 10
-2 -3 -1 4 -3 2 0 1 -5 4
 5
30 -29 10 -1 10
 31
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -29 30
 7
30 -20 5 1 3 -20 30
 5
30 -29 4 -3 4
 10
-5 28 -18 -10 9 -2 11 -6 -19 30
 8
4 -10 13 -13 2 2 -11 6
 131
30 -29 29 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 28 -28 27 -26 27
 10
-4 4 0 -2 3 0 1 2 3 -4
 10
-2 -8 5 4 -1 -6 -9 6 1 -6
 7
25 -17 13 13 -25 25 -24
 10
3 -3 2 1 -4 -2 3 -2 -3 0
 10
4 -5 0 4 0 0 -3 1 1 -4
 10
0 4 4 1 -3 4 2 1 4 -1
 17
15 -13 7 8 8 1 -19 12 8 -23 -4 16 -13 -28 10 -30 -14
 4
1 1 -4 10
 11
3 -2 1 1 1 1 1 1 1 -3 4
 7
30 -29 10 10 10 -29 30
 7
25 -13 17 -23 12 12 9
 7
15 -14 10 10 10 -14 15
 10
3 0 0 -4 3 1 -2 -1 -1 4
 6
8 -7 7 -6 5 5
 10
1 -4 -4 4 -2 -3 3 0 -2 3
 15
1 -26 -6 26 7 10 -2 -4 -6 14 -9 25 9 -12 -28
 6
30 -29 10 10 -29 30
 1
6
 2
1 1
 5
0 5 -4 3 -1
 7
5 -4 3 -1 3 -4 4
 10
16 -15 13 -1 10 -2 -20 26 5 -30
 10
-1 2 0 -1 2 -1 4 3 -5 1
 7
5 -4 1 1 1 -4 5
 5
10 -3 -5 3 5
 10
4 -4 3 -2 3 -4 -2 0 1 0
 10
-5 -5 -3 1 -2 2 0 2 -3 4
 10
2 -4 -2 3 1 1 -2 -1 -3 4
 10
-4 -5 4 -3 2 -2 2 1 -1 0
 10
0 -1 4 -2 3 -2 -1 -5 -5 2
 5
19 -6 1 -11 19
 10
1 0 -4 3 -5 3 -1 2 2 -5
 7
5 -5 3 4 3 -5 5
 10
-5 2 -3 -3 -4 3 3 0 2 4
 4
2 3 -10 11
 10
27 -17 15 -22 18 17 -6 2 16 -14
 6
30 -22 6 7 -22 30
 7
30 -25 0 6 9 -2 10
 9
7 2 -1 1 1 -10 6 -1 6
 4
1 -10 1 10
 5
17 -16 12 -11 15
 35
-23 -22 23 4 -22 29 -4 -6 -28 18 -5 21 -7 -8 -11 -7 30 -25 -1 12 19 5 -8 12 -1 10 -24 -19 24 -17 -7 24 20 -22 16
 10
4 -3 1 -2 1 1 0 -4 4 -2
 10
4 -2 1 0 1 -5 -2 1 0 -5
 2
3 9
 9
11 -5 -5 1 2 3 -5 -5 11

1
 8
 1
 4
 1
 2
 15
 5
 36
 2
 3
 1
 9
 28
 4
 1
 7
 2
 1
 7
 4
 13
 1
 1
 13
 16
 1
 6
 20
 21
 20
 1
 5
 1
 44
 10
 0
 1
 0
 2
 9
 5
 2
 3
 1
 2
 2
 1
 1
 3
 3
 6
 8
 2
 29
 6
 13
 5
 1
 1
 30
 1
 1
 3
 3

#include <bits/stdc++.h>
using namespace std;
long long md = 998244353LL;
long long inf;
int p[100000] = {0};
int nx[100000] = {0};
long long x2[100000][20];
long long x1[100000][20];
long long getmn(int i, int j, int n, bool f) {
  bool f1 = false, f2 = false;
  if (i == -1) i = 0, f1 = true;
  if (j == -1) j = n - 1, f2 = true;
  int l = 1;
  int s = 0;
  while (i + l - 1 <= j) {
    l *= 2;
    s++;
  }
  s--;
  l /= 2;
  long long ret;
  if (f) {
    ret = min(x1[i][s], x1[j - l + 1][s]);
    if (f1) return min(ret, 0LL);
  } else {
    ret = min(x2[i][s], x2[j - l + 1][s]);
    if (f2) return min(ret, 0LL);
  }
  return ret;
}
int main() {
  ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  inf = md * md;
  inf *= 8;
  inf++;
  int test = 1;
  for (int t = 1; t <= test; t++) {
    int n;
    cin >> n;
    int a[n];
    for (int i = 0; i < n; i++) {
      cin >> a[i];
    };
    long long s1[n];
    s1[0] = a[0];
    long long s2[n];
    s2[n - 1] = a[n - 1];
    x1[0][0] = a[0];
    x2[n - 1][0] = a[n - 1];
    int i = 1;
    while (i < n) {
      s1[i] = s1[i - 1] + a[i];
      x1[i][0] = s1[i];
      i++;
    }
    i = n - 2;
    while (i >= 0) {
      s2[i] = s2[i + 1] + a[i];
      x2[i][0] = s2[i];
      i--;
    }
    i = 2;
    int j = 1;
    while (i <= n) {
      int k = i / 2;
      int f = 0;
      while (f < n) {
        if (f + i - 1 >= n) break;
        x1[f][j] = min(x1[f][j - 1], x1[f + k][j - 1]);
        f++;
      }
      f = n - 1;
      while (f >= 0) {
        if (f + i - 1 >= n) {
          f--;
          continue;
        }
        x2[f][j] = min(x2[f][j - 1], x2[f + k][j - 1]);
        f--;
      }
      i *= 2;
      j++;
    }
    p[0] = -1;
    int v[61];
    for (int i = 0; i < 61; i++) v[i] = -1;
    ;
    j = a[0];
    while (j >= (-30)) v[30 + j] = 0, j--;
    i = 1;
    while (i < n) {
      p[i] = -1;
      j = a[i];
      while (j >= (-30)) v[30 + j] = i, j--;
      if (a[i] == 30) {
        i++;
        continue;
      }
      j = a[i] + 1;
      while (j <= 30) {
        if (v[30 + j] >= 0) {
          p[i] = v[30 + j];
          break;
        }
        j++;
      }
      i++;
    }
    i = n - 2;
    for (int i = 0; i < 61; i++) v[i] = -1;
    ;
    v[30 + a[n - 1]] = n - 1;
    j = a[n - 1];
    while (j >= (-30)) v[30 + j] = n - 1, j--;
    nx[n - 1] = -1;
    while (i >= 0) {
      nx[i] = -1;
      j = a[i];
      while (j >= (-30)) v[30 + j] = i, j--;
      if (a[i] == 30) {
        i--;
        continue;
      }
      j = a[i] + 1;
      while (j <= 30) {
        if (v[30 + j] >= 0) {
          nx[i] = v[30 + j];
          break;
        }
        j++;
      }
      i--;
    }
    i = 0;
    long long ans = 0;
    while (i < n) {
      long long sp = 0, sn = 0;
      if (i > 0) {
        j = p[i];
        sp = s1[i - 1] - getmn(j, i - 1, n, 1);
      }
      if (i < n - 1) {
        j = nx[i];
        sn = s2[i + 1] - getmn(i + 1, j, n, 0);
      }
      ans = max(ans, sp + sn);
      i++;
    }
    cout << ans << endl;
  }
  return 0;
}
