#include <bits/stdc++.h> using namespace std; typedef long long ll; #define REP(i,n) for(int i=0,_n=(int)(n);i<_n;++i) #define ALL(v) (v).begin(),(v).end() template<class T1,class T2>ostream& operator<<(ostream& os,const pair<T1,T2>&a){return os<<"("<<a.first<<","<<a.second<< ")";} template<class T>void pv(T a,T b){for(T i=a;i!=b;++i)cout<<(*i)<<" ";cout<<endl;} template<class T>bool chmin(T&a,const T&b){return a>b?(a=b,1):0;} template<class T>bool chmax(T&a,const T&b){return a<b?(a=b,1):0;} int nextInt() { int x; scanf("%d", &x); return x;} int main2() { string s; cin >> s; int ans = 0; int N = s.size(); for (int i = 0; i < N; i++) { for (int j = 0; j + 1 < N; j++) { if (s[j] > s[j+1]) { swap(s[j], s[j+1]); ans++; } } } cout << ans << endl; } int main() { for (;!cin.eof();cin>>ws) main2(); return 0; }