#include <bits/stdc++.h>

using namespace std;

int main () {
  string s;
  cin >> s;
  
  int n = (int)s.size();
  string t = s;
  sort(s.begin(), s.end, greater<char>());
  int cnt = 0;
  for (int i = 0; i < n; ++i) {
    if (s[i] != t[i]) cnt++;
  }
  cout << n - cnt << endl;
  return 0;
}
