#include <bits/stdc++.h>
using namespace std;
const long long MAX = (long long)1e18;
const long long INF = (long long)1e18;
const long long MIN = (long long)-1e18;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T>
void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x) cerr << (f++ ? ", " : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
struct segminidx {
  long long sz;
  vector<array<long long, 4>> v;
  segminidx(long long n) {
    sz = 1;
    while (sz < n) sz *= 2;
    v.assign(2 * sz, {0, 0, 0, 0});
  }
  array<long long, 4> merge(array<long long, 4> a1, array<long long, 4> a2) {
    if (a1[0] < a2[0]) return a1;
    if (a2[0] < a1[0]) return a2;
    return {a1[0], a1[1] + a2[1], min(a1[2], a2[2]), max(a1[3], a2[3])};
  }
  void build(vector<long long> &a, long long x, long long lx, long long rx) {
    if (rx - lx == 1) {
      if (lx < a.size()) {
        v[x] = {a[lx], 1, lx, lx};
      }
      return;
    }
    long long m = (lx + rx) / 2;
    build(a, 2 * x + 1, lx, m);
    build(a, 2 * x + 2, m, rx);
    v[x] = merge(v[2 * x + 1], v[2 * x + 2]);
  }
  void build(vector<long long> &a) { build(a, 0, 0, sz); }
  void set(long long i, long long va, long long x, long long lx, long long rx) {
    if (rx - lx == 1) {
      v[x] = {va, 1, i, i};
      return;
    }
    long long m = (lx + rx) / 2;
    if (i < m)
      set(i, va, 2 * x + 1, lx, m);
    else
      set(i, va, 2 * x + 2, m, rx);
    v[x] = merge(v[2 * x + 1], v[2 * x + 2]);
  }
  void set(long long i, long long va) { set(i, va, 0, 0, sz); }
  array<long long, 4> findmin(long long l, long long r, long long x,
                              long long lx, long long rx) {
    if (lx >= r || rx <= l) {
      return {INF, 0, INF, -INF};
    }
    if (lx >= l && rx <= r) {
      return v[x];
    }
    array<long long, 4> a1, a2;
    long long m = (lx + rx) / 2;
    a1 = findmin(l, r, 2 * x + 1, lx, m);
    a2 = findmin(l, r, 2 * x + 2, m, rx);
    return merge(a1, a2);
  }
  array<long long, 4> findmin(long long l, long long r) {
    return findmin(l, r, 0, 0, sz);
  }
};
struct segmaxidx {
  long long sz;
  vector<array<long long, 4>> v;
  segmaxidx(long long n) {
    sz = 1;
    while (sz < n) sz *= 2;
    v.assign(2 * sz, {0, 0, 0, 0});
  }
  array<long long, 4> merge(array<long long, 4> a1, array<long long, 4> a2) {
    if (a1[0] < a2[0]) return a2;
    if (a2[0] < a1[0]) return a1;
    return {a1[0], a1[1] + a2[1], min(a1[2], a2[2]), max(a1[3], a2[3])};
  }
  void build(vector<long long> &a, long long x, long long lx, long long rx) {
    if (rx - lx == 1) {
      if (lx < a.size()) {
        v[x] = {a[lx], 1, lx, lx};
      }
      return;
    }
    long long m = (lx + rx) / 2;
    build(a, 2 * x + 1, lx, m);
    build(a, 2 * x + 2, m, rx);
    v[x] = merge(v[2 * x + 1], v[2 * x + 2]);
  }
  void build(vector<long long> &a) { build(a, 0, 0, sz); }
  void set(long long i, long long va, long long x, long long lx, long long rx) {
    if (rx - lx == 1) {
      v[x] = {va, 1, i, i};
      return;
    }
    long long m = (lx + rx) / 2;
    if (i < m)
      set(i, va, 2 * x + 1, lx, m);
    else
      set(i, va, 2 * x + 2, m, rx);
    v[x] = merge(v[2 * x + 1], v[2 * x + 2]);
  }
  void set(long long i, long long va) { set(i, va, 0, 0, sz); }
  array<long long, 4> findmax(long long l, long long r, long long x,
                              long long lx, long long rx) {
    if (lx >= r || rx <= l) {
      return {-INF, 0, INF, -INF};
    }
    if (lx >= l && rx <= r) {
      return v[x];
    }
    array<long long, 4> a1, a2;
    long long m = (lx + rx) / 2;
    a1 = findmax(l, r, 2 * x + 1, lx, m);
    a2 = findmax(l, r, 2 * x + 2, m, rx);
    return merge(a1, a2);
  }
  array<long long, 4> findmax(long long l, long long r) {
    return findmax(l, r, 0, 0, sz);
  }
};
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long n;
  cin >> n;
  vector<long long> a(n);
  for (long long i = 0; i < n; ++i) {
    cin >> a[i];
  }
  vector<long long> pref(n + 1);
  pref[0] = 0;
  for (long long i = 1; i <= n; ++i) {
    pref[i] = pref[i - 1] + a[i - 1];
  }
  segminidx smin(n + 1);
  segmaxidx smax(n + 1);
  smin.build(pref);
  smax.build(pref);
  vector<long long> r(n), l(n);
  r[n - 1] = n;
  l[0] = -1;
  for (long long i = 1; i < n; ++i) {
    long long j = i - 1;
    while (j >= 0 && a[j] <= a[i]) {
      j = l[j];
    }
    l[i] = j;
  }
  for (long long i = n - 2; i >= 0; --i) {
    long long j = i + 1;
    while (j < n && a[j] <= a[i]) {
      j = r[j];
    }
    r[i] = j;
  }
  long long ans = MIN;
  for (long long i = 0; i < n; ++i) {
    long long res = 0;
    array<long long, 4> q1, q2;
    if (r[i] != n)
      q1 = smax.findmax(i + 1, r[i] + 1);
    else
      q1 = smax.findmax(i + 1, n + 1);
    if (l[i] != -1)
      q2 = smin.findmin(l[i] + 2, i + 2);
    else
      q2 = smin.findmin(0, i + 2);
    if (q1[3] == q2[2]) {
      res = 0;
    } else {
      res = q1[0] - q2[0] - a[i];
    }
    ans = max(ans, res);
  }
  cout << ans << endl;
  return 0;
}
