#include <bits/stdc++.h>
const double PI = 3.141592653589793238463;
using namespace std;
inline long long add(long long a, long long b) {
  a += b;
  if (a >= 1000000007) a -= 1000000007;
  return a;
}
inline long long sub(long long a, long long b) {
  a -= b;
  if (a < 0) a += 1000000007;
  return a;
}
inline long long mul(long long a, long long b) {
  return (long long)((long long)a * b % 1000000007);
}
long long fast_power(long long base, long long power) {
  long long result = 1;
  while (power > 0) {
    if (power % 2 == 1) {
      result = (result * base) % 1000000007;
    }
    base = (base * base) % 1000000007;
    power = power / 2;
  }
  return result;
}
long long min(long long a, long long b) { return a > b ? b : a; }
long long max(long long a, long long b) { return a > b ? a : b; }
void dfs(long long s, vector<vector<long long>> &adj, vector<bool> &vis,
         vector<long long> &arr) {
  if (vis[s]) return;
  vis[s] = true;
  arr.push_back(s);
  for (auto x : adj[s]) {
    if (vis[x] == false) {
      dfs(x, adj, vis, arr);
    }
  }
}
void bfs(long long x, vector<bool> &vis, vector<vector<long long>> &adlist,
         vector<long long> &level, vector<long long> &parent) {
  queue<long long> q;
  vis[x] = true;
  q.push(x);
  while (!q.empty()) {
    long long s = q.front();
    q.pop();
    for (auto u : adlist[s]) {
      if (vis[u]) continue;
      vis[u] = true;
      parent[u] = s;
      level[u] = level[s] + 1;
      q.push(u);
    }
  }
}
bool bpchk(vector<vector<long long>> &adj, vector<long long> &color) {
  color[1] = 1;
  queue<long long> q;
  q.push(1);
  while (!q.empty()) {
    long long u = q.front();
    q.pop();
    for (auto x : adj[u]) {
      if (color[x] == -1) {
        color[x] = color[u] ^ 1;
        q.push(x);
      }
    }
  }
  for (long long i = 1; i < adj.size(); i++) {
    for (auto x : adj[i]) {
      if (color[x] == color[i]) return false;
    }
  }
  return true;
}
void swap(long long *a, long long *b) {
  long long tmp = *a;
  *a = *b;
  *b = tmp;
}
void SieveOfEratosthenes(long long n, set<long long> &s) {
  vector<bool> prime(n + 1, true);
  for (long long p = 2; p * p <= n; p++) {
    if (prime[p] == true) {
      for (long long i = p * p; i <= n; i += p) prime[i] = false;
    }
  }
  for (long long p = 2; p <= n; p++)
    if (prime[p]) s.insert(p);
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  string s;
  cin >> s;
  int n = s.size();
  int dp[n + 1];
  dp[0] = 0;
  long long cnt = 0;
  for (int i = 1; i <= n; i++) {
    if (s[i - 1] == 'M') {
      dp[i] = dp[i - 1];
    } else
      dp[i] = (cnt > 0) ? max(dp[i - 1] + 1, cnt) : 0;
    if (s[i - 1] == 'M') cnt += 1;
  }
  cout << dp[n] << "\n";
}
