#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;
int main() {
  string s;
  cin >> s;
  int ans1 = 0, ans2 = 0;
  for (int i = s.size() - 1; i >= 0; i--) {
    if (s[i] == 'S') {
      ans1 += 2;
    } else {
      break;
    }
  }
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == 'T') {
      ans2 += 2;
    } else {
      break;
    }
  }
  cout << (max(ans1, ans2)) << '\n';
}
