#include <bits/stdc++.h>
using namespace std;
const int maxn = 100010;
const int mod = 1e9 + 7;
const int MAX = 1000000010;
const double eps = 1e-6;
const double PI = acos(-1);
template <typename T>
inline void read(T &x) {
  x = 0;
  T f = 1;
  char ch;
  do {
    ch = getchar();
    if (ch == '-') f = -1;
  } while (ch < '0' || ch > '9');
  do x = x * 10 + ch - '0', ch = getchar();
  while (ch <= '9' && ch >= '0');
  x *= f;
}
template <typename A, typename B>
inline void read(A &x, B &y) {
  read(x);
  read(y);
}
template <typename A, typename B, typename C>
inline void read(A &x, B &y, C &z) {
  read(x);
  read(y);
  read(z);
}
template <typename A, typename B, typename C, typename D>
inline void read(A &x, B &y, C &z, D &w) {
  read(x);
  read(y);
  read(z);
  read(w);
}
template <typename A, typename B>
inline A fexp(A x, B p) {
  A ans = 1;
  for (; p; p >>= 1, x = 1LL * x * x % mod)
    if (p & 1) ans = 1LL * ans * x % mod;
  return ans;
}
template <typename A, typename B>
inline A fexp(A x, B p, A mo) {
  A ans = 1;
  for (; p; p >>= 1, x = 1LL * x * x % mo)
    if (p & 1) ans = 1LL * ans * x % mo;
  return ans;
}
int n, cnt;
char st[20];
pair<long long, long long> A[maxn];
long long sm[maxn];
void Work() {
  long long ans = 0;
  int x;
  read(x);
  ans += x;
  bool ok = 0;
  long long pos, tot;
  for (int i = (2); i <= (n); i++) {
    scanf("%s", st);
    read(x);
    if (!ok) {
      if (st[0] == '+')
        ans += x;
      else {
        ok = 1;
        pos = x;
        tot = 0;
      }
    } else {
      if (st[0] == '+')
        tot += x;
      else {
        A[++cnt] = make_pair(pos, tot);
        pos = x;
        tot = 0;
      }
    }
  }
  A[++cnt] = make_pair(pos, tot);
  long long mx = 0;
  for (int i = (1); i <= (cnt); i++) mx += A[i].second - A[i].first;
  for (int i = (cnt); i >= (1); i--)
    sm[i] = sm[i + 1] + A[i].first + A[i].second;
  long long now = 0;
  for (int i = (1); i <= (cnt); i++) {
    mx = max(mx, now + sm[i + 1] - A[i].first - A[i].second);
    now += A[i].second - A[i].first;
  }
  cout << mx + ans << endl;
}
void Init() { read(n); }
int main() {
  Init();
  Work();
  return 0;
}
