#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
template <class T>
inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmin(T &a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
struct io {
  io() {
    ios::sync_with_stdio(false);
    cin.tie(0);
  }
};
const int INF = INT_MAX;
const long long int LLINF = 1LL << 60;
const long long int MOD = 1000000007;
const double EPS = 1e-9;
string replaceOtherStr(std::string &replacedStr, std::string from,
                       std::string to) {
  const long long int pos = replacedStr.find(from);
  const long long int len = from.length();
  if (pos == (long long int)std::string::npos || from.empty()) {
    return replacedStr;
  }
  return replacedStr.replace(pos, len, to);
}
signed main(void) {
  string s;
  cin >> s;
  while (true) {
    string s2 = s;
    replaceOtherStr(s, "ST", "");
    if (s == s2) break;
  }
  cout << (s.length()) << endl;
}
