#include <bits/stdc++.h>
using namespace std;
int main() {
  string S;
  cin >> S;
  int count = 0, ans = 0;
  for (int i = 0; i < S.size(); i++) {
    if (S[i] == 'T')
      count++;
    else
      count--;
    if (count > ans) ans = count;
  }
  cout << ans << endl;
}
