#include <bits/stdc++.h>
using namespace std;

#define int long long

void testcase() {
  int N;
  cin >> N;
  vector<char> S(N);
  for (int i = 0; i < N; i++) { cin >> S[i]; }

  vector<int> J(N);
  int plus = 0, minus = 0;
  for (int i = 0; i < N; i++) {
    if (S[i] == '+') {
      plus++;
      J[i] = plus;
    } else if (S[i] == '-') {
      minus--;
      J[i] = minus;
    } else {
      J[i] = 0;
    }
  }

  int cu = 0;
  vector<int> fixed(N);
  for (int i = 0; i < N; i++) {
    if (cu == 0) {
      if (J[i] == minus) {
        fixed[cu] = minus;
        cu++;
      }
    } else {
      if (J[i - 1] < J[i]) {
        fixed[cu] = J[i];
        if (J[cu] == plus) { break; }
        cu++;
      }
    }
  }

  cout << J[cu] - J[0] << "\n";
}

int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  testcase();
  return 0;
}