#include <bits/stdc++.h>
using namespace std;
int a[1000010];
int main() {
  char str;
  int i, n, x, maxn = 0, num = 0;
  cin >> n;
  while (n--) {
    cin >> str >> x;
    if (str == '+') {
      num++;
      a[x] = 1;
      maxn = max(maxn, num);
    } else {
      if (a[x]) {
        num--;
        a[x] = 0;
      } else {
        maxn++;
      }
    }
  }
  cout << maxn << endl;
  return 0;
}
