#include <bits/stdc++.h>
using namespace std;
char s[1000100];
int n;
int d[1000100];
int dp(int x) {
  if (d[x] != -1) return d[x];
  int ret = 0;
  int ind = x + 1;
  while (s[ind] == 'M') {
    ret += 1;
    ind++;
  }
  int w = 0;
  while (s[ind] == 'F' && ind < n) ind++, w++;
  if (ind == n)
    return d[x] = ret;
  else {
    int rety = dp(ind);
    if (w > rety)
      return d[x] = ret;
    else
      return d[x] = dp(ind) + 1 - w + ret;
  }
}
int main() {
  while (scanf("%s", s) != EOF) {
    n = strlen(s);
    memset(d, -1, sizeof(d));
    int cntm = 0;
    for (int i = 0; i < n; i++)
      if (s[i] == 'M') cntm++;
    for (int i = n - 1; i >= 0; i--) {
      if (s[i] == 'M')
        d[i] = 0;
      else
        break;
    }
    int st = -1;
    for (int i = 0; i < n; i++)
      if (s[i] == 'M') {
        st = i;
        break;
      }
    if (st == -1) {
      puts("0");
      continue;
    }
    dp(st);
    printf("%d\n", d[st] + (n - 1 - cntm + 1) - st);
  }
  return 0;
}
