#include <iostream>                   
#include <string>                     
#include <algorithm>                  
#include <cctype>                     
#include <cstring>                    
#include <ctime>                      
using namespace std;                  
const int maxint=26;                  
int hash1[26];                        
int perfect(const string &s)          
{                                     
	memset(hash1,0,sizeof(hash1));       
	for(int i=0;i!=s.size();i++){        
		if(!isalpha(s[i]))continue;         
		char tmp=tolower(s[i]);             
		hash1[tmp-'a']++;                   
		                                    
	}                                    
	int sum=0;                           
	sort(hash1,hash1+26);                
	int tmp=maxint;                      
	for(int i=25;i>=0;i--)               
	{                                    
		if(!hash1[i])continue;              
		sum+=hash1[i]*tmp;                  
		tmp--;                              
	}                                    
	return sum;	                         
}                                     
int main()                            
{                                     
	string s="dd//BCD..aa";      
	//clock_t start,end;                   
	//start=clock();                       
	cout<<perfect(s)<<endl;              
	//end=clock();                         
	//cout<<end-start<<endl;               
	return 0;                            
}