#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <vector>
#include <cmath>
#include <string>
#include <sstream>
#include<sstream>
#include <queue>
#include <limits>
#include <cstdlib>
#include <deque>
#include <map>
#include <set>
#include <iomanip>
using namespace std;



int main() {

	string s;

	cin>>s;

	int len = s.length();

	bool judge = true;
	string tmp;
	int count =0;
	while(judge){
		judge =false;
		for(int k = 0 ; k <len-1; k++){
			if(s[k] > s[k+1]){
				tmp = s[k];
				s.replace(k,1,s.substr(k+1,1));
				s.replace(k+1,1 ,tmp);
				count++;
				judge = true;
			}
		}
	}

	/*cout<<s<<endl;*/
	cout<<count<<endl;


	return 0;
}