#include <bits/stdc++.h>
using namespace std;
using int64 = long long;
int main() {
  int N, A[100000];
  char op[100000];
  cin >> N;
  cin >> A[0];
  for (int i = 1; i < N; i++) {
    cin >> op[i] >> A[i];
  }
  int64 all = A[0];
  for (int i = 1; i < N; i++) {
    if (op[i] == '+')
      all += A[i];
    else
      all -= A[i];
  }
  int64 cost = 0, ans = all, add = 0;
  for (int i = N - 1; i > 0; i--) {
    if (op[i] == '+') {
      cost += 2 * A[i];
    } else {
      ans = max(ans, ans + add - cost);
      add += 2 * A[i];
      cost = 0;
    }
  }
  cout << ans << endl;
}
