#pragma GCC optimize("Ofast","unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define int long long
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
const int G = 10;
vector<vector<int>> groups(G);
string s;
cin >> s;
int N = s.size();
for(int i=0;i<N;i++){
groups[s[i]-'A'].emplace_back(i+1);
}
vector<int> DP((1<<G),1e12);
DP[0]=0;
for(int mask=1;mask<(1<<G);mask++){
vector<pair<int,int>> arr;
int tot = 0;
for(int x=0;x<G;x++)if(mask&(1<<x)){
for(int&i:groups[x])arr.emplace_back(i,x);
tot+=groups[x].size();
}
ranges::sort(arr);
for(int top=0;top<G;top++)if(mask&(1<<top)){
int ans = 0;
int currOther = 0;
int currMine = 0;
for(auto&[i,type]:arr){
if(type!=top){
currOther++;
continue;
}
ans+=min(currMine+2ll*currOther,(int)((int)groups[top].size()-1ll-currMine+2ll*(tot-groups[top].size()-currOther)));
currMine++;
}
DP[mask]=min(DP[mask],DP[mask^(1<<top)]+ans);
}
}
cout << DP[(1<<G)-1]/2;
if(DP[(1<<G)-1]&1)cout<<".5";
cout << '\n';
}
