#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using PII = pair<ll, ll>;
template <typename T>
using V = vector<T>;
template <typename T>
using VV = vector<V<T>>;
template <typename T>
using VVV = vector<VV<T>>;
const ll INF = (1LL << 60);
const ll MOD = 1000000007;
template <typename T>
T &chmin(T &a, const T &b) {
  return a = min(a, b);
}
template <typename T>
T &chmax(T &a, const T &b) {
  return a = max(a, b);
}
template <typename T>
bool IN(T a, T b, T x) {
  return a <= x && x < b;
}
template <typename T>
T ceil(T a, T b) {
  return a / b + !!(a % b);
}
template <class S, class T>
ostream &operator<<(ostream &out, const pair<S, T> &a) {
  out << '(' << a.first << ',' << a.second << ')';
  return out;
}
template <class T>
ostream &operator<<(ostream &out, const vector<T> &a) {
  out << '[';
  for (ll i = (ll)0; i < (ll)a.size(); ++i) {
    out << a[i];
    if (i != a.size() - 1) out << ',';
  }
  out << ']';
  return out;
}
ll dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};
signed main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll n;
  cin >> n;
  V<ll> a(n);
  V<char> op(n);
  op[0] = '+';
  cin >> a[0];
  for (ll i = (ll)1; i < (ll)n; ++i) cin >> op[i] >> a[i];
  V<ll> b(n);
  b[0] = a[0];
  for (ll i = (ll)1; i < (ll)n; ++i) b[i] = b[i - 1] + a[i];
  V<ll> v;
  for (ll i = (ll)0; i < (ll)n; ++i)
    if (op[i] == '-') v.push_back(i);
  V<ll> nxt(n);
  for (ll i = (ll)0; i < (ll)v.size() - 1; ++i) nxt[v[i]] = v[i + 1];
  nxt[v.back()] = n;
  ll now = 0;
  for (ll i = (ll)0; i < (ll)n; ++i) {
    if (op[i] == '+')
      now += a[i];
    else
      now -= a[i];
  }
  ll ret = now;
  now = 0;
  for (ll i = (ll)0; i < (ll)n; ++i) {
    if (op[i] == '+') {
      now += a[i];
    } else {
      chmax(ret, now - (b[nxt[i] - 1] - b[i - 1]) + (b[n - 1] - b[nxt[i] - 1]));
      now -= a[i];
    }
  }
  cout << ret << endl;
  return 0;
}
