#include <bits/stdc++.h>
using namespace std;
inline long long readInt();
inline void printInt(long long x);
void SOLVE() {
  string str;
  cin >> str;
  int ctr = 0, ans = 0;
  for (int i = 0; i < str.length(); i++) {
    if (str[i] == '+') {
      ctr++;
      if (ctr > ans) ans++;
    } else {
      ctr--;
      if (ctr < 0) {
        ctr++;
        ans++;
      }
    }
  }
  cout << ans << endl;
}
int main() {
  double _time = clock();
  if (0) freopen("input.txt", "r", stdin);
  SOLVE();
  if (0) printf("Exec time: %0.6f sec\n", (clock() - _time) / CLOCKS_PER_SEC);
  return 0;
}
inline long long readInt() {
  register int c = getchar();
  long long x = 0, neg = 0;
  for (; ((c < '0' || c > '9') && c != '-'); c = getchar())
    ;
  if (c == '-') {
    neg = 1;
    c = getchar();
  }
  for (; c >= '0' && c <= '9'; c = getchar()) x = x * 10 + (c - '0');
  return (neg) ? -x : x;
}
inline void printInt(long long x) {
  char pri[30];
  int i = 0;
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  do {
    pri[i++] = (x % 10) + '0';
    x /= 10;
  } while (x != 0);
  for (int j = (i - 1); j > (0 - 1); j -= 1) putchar(pri[j]);
}
