#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
template <typename X>
inline X abs(const X& a) {
  return a < 0 ? -a : a;
}
template <typename X>
inline X sqr(const X& a) {
  return a * a;
}
const int size = 1e5 + 5;
const double eps = 0.0001;
const long double PI = 3.1415926535897932384626433832795;
const long long MOD = 1000000007;
const long long INF = 1LL << 62;
const long long MAX5 = 100001;
const long long MAX6 = 1000001;
const long long MAX17 = 99999999999999999;
const double DMAX = 2e18 + 5;
void solution();
void include_file();
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  solution();
  return 0;
}
inline void include_file() {
  ios_base::sync_with_stdio(true);
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
inline bool isPrime(long long n) {
  for (int i = 2; i * i <= n; ++i)
    if (n % i == 0) return false;
  return true;
}
inline string ekv(string a) {
  if (a.size() & 1) return a;
  string x = ekv(a.substr(0, a.size() / 2));
  string y = ekv(a.substr(a.size() / 2));
  return min(x + y, y + x);
}
inline long long cubic_root(long long x) {
  long long l = 0, r = MAX6;
  while (l != r) {
    long long m = (l + r + 1) / 2;
    if (m * m * m > x)
      r = m - 1;
    else
      l = m;
  }
  return l;
}
inline float FastInvSqrt(float x) {
  float xhalf = 0.5f * x;
  int i = *(int*)&x;
  i = 0x5f3759df - (i >> 1);
  x = *(float*)&i;
  x = x * (1.5f - (xhalf * x * x));
  return x;
}
inline long long gcd(long long a, long long b) {
  while (b ^= a ^= b ^= a = a % b)
    ;
  return a;
}
inline long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
constexpr uint64_t mod = (1ull << 61) - 1;
inline uint64_t modmul(uint64_t a, uint64_t b) {
  uint64_t l1 = (uint32_t)a, h1 = a >> 32, l2 = (uint32_t)b, h2 = b >> 32;
  uint64_t l = l1 * l2, m = l1 * h2 + l2 * h1, h = h1 * h2;
  uint64_t ret =
      (l & mod) + (l >> 61) + (h << 3) + (m >> 29) + (m << 35 >> 3) + 1;
  ret = (ret & mod) + (ret >> 61);
  ret = (ret & mod) + (ret >> 61);
  return ret - 1;
}
void yes() { cout << "YES"; }
void no() { cout << "NO"; }
void yes(bool res, bool small = false) {
  if (!small) {
    if (res)
      cout << "YES";
    else
      cout << "NO";
  } else {
    if (res)
      cout << "Yes";
    else
      cout << "No";
  }
}
void dabl(double x) { printf("%.10lf", x); }
namespace bits {
template <typename X>
inline X MAX(const X& a, const X& b) {
  return b & ((a - b) >> 31) | a & (~(a - b) >> 31);
}
template <typename X>
inline X MIN(const X& a, const X& b) {
  return a & ((a - b) >> 31) | b & (~(a - b) >> 31);
}
inline bool check2(const long long n) { return n > 0 && (n & (n - 1)); }
inline long long ostatok2(const long long n, const long long m) {
  return m & (n - 1);
}
template <typename X>
inline void SWAP(X& a, X& b) {
  a ^= b;
  b ^= a;
  a ^= b;
}
inline size_t count_1_in_LL(unsigned long long n) {
  std::size_t i(0);
  for (; n; ++i) n &= n - 1;
  return i;
}
}  // namespace bits
void debug() { cout << endl; }
template <typename H, typename... T>
void debug(H p, T... t) {
  std::cout << p << " ";
  debug(t...);
}
vector<vector<int> > g;
inline void solution() {
  string s;
  cin >> s;
  int res = 0;
  int q = 0, z = 0;
  for (long long i = 0; i < s.size(); ++i) {
    if (s[i] == '+')
      q++, z = max(z - 1, 0);
    else
      z++, q = max(q - 1, 0);
  }
  res = q + z;
  ;
  cout << res;
  ;
}
