#include <bits/stdc++.h>
using namespace std;
template <typename T, class F = function<T(const T&, const T&)>>
class SparseTable {
 public:
  int n;
  vector<vector<T>> sp;
  F func;
  SparseTable(const vector<T>& a, const F& f) : func(f) {
    n = static_cast<int>(a.size());
    int max_log = 32 - __builtin_clz(n);
    sp.resize(max_log);
    sp[0] = a;
    for (int j = 1; j < max_log; ++j) {
      sp[j].resize(n - (1 << j) + 1);
      for (int i = 0; i <= n - (1 << j); ++i) {
        sp[j][i] = func(sp[j - 1][i], sp[j - 1][i + (1 << (j - 1))]);
      }
    }
  }
  T get(int l, int r) const {
    int lg = 32 - __builtin_clz(r - l + 1) - 1;
    return func(sp[lg][l], sp[lg][r - (1 << lg) + 1]);
  }
};
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int n;
  cin >> n;
  vector<int> a(n + 1), nxt(n + 1), prv(n + 1), cum(n + 1);
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    cum[i] = cum[i - 1] + a[i];
  }
  for (int i = n; i >= 1; i--) {
    nxt[i] = i + 1;
    while (nxt[i] <= n && a[nxt[i]] <= a[i]) nxt[i] = nxt[nxt[i]];
  }
  for (int i = 1; i <= n; i++) {
    prv[i] = i - 1;
    while (prv[i] >= 1 && a[prv[i]] <= a[i]) prv[i] = prv[prv[i]];
  }
  SparseTable<int> mn_sp(cum, [&](int i, int j) { return min(i, j); });
  SparseTable<int> mx_sp(cum, [&](int i, int j) { return max(i, j); });
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    int l = prv[i] + 1, r = nxt[i] - 1;
    ans = max(ans, mx_sp.get(i, r) - mn_sp.get(l - 1, i - 1) - a[i]);
  }
  cout << ans;
}
