#include <bits/stdc++.h>
using namespace std;
long long n, a[120000], b[120000], x, tail, tot;
char s[10];
int main() {
  scanf("%lld", &n);
  scanf("%lld", &a[1]);
  tail = 1;
  tot = a[1];
  for (int i = 2; i <= n; i++) {
    scanf("%s", s + 1);
    scanf("%lld", &x);
    tot += x;
    if (s[1] == '-') {
      tail++;
      a[tail] = x;
      b[tail] = x;
    } else
      a[tail] += x;
  }
  long long ans = 1000000000000000000LL, bns = 0;
  for (int i = 2; i <= tail; i++) {
    ans = min(ans, bns + a[i]);
    bns += b[i];
  }
  printf("%lld\n", tot - 2 * ans);
}
