/*
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 * and open the template in the editor.
 */


import java.util.*;

/**
 *
 * @author ankit
 */
public class password {
    
    public static void main(String args[])
    {
        Scanner sc=new Scanner(System.in);
        int n;
        n=sc.nextInt();
        String s;
        s=sc.next();
        int count=0;
        int cd,cl,cu,cs;
        cd=cs=cl=cu=0;
        for(int i=0;i<n;i++)
        {
            //System.out.println(Character.getNumericValue(s.charAt(i)));
           
           if(s.charAt(i)=='!'||s.charAt(i)=='@'||s.charAt(i)=='#'||s.charAt(i)=='$'||s.charAt(i)=='%'||s.charAt(i)=='^'||s.charAt(i)=='&'||s.charAt(i)=='*'||s.charAt(i)=='('||s.charAt(i)==')'||s.charAt(i)=='-'||s.charAt(i)=='+')
        {
        
        cs=1;
        
        
        }
        
           else if(Character.getNumericValue(s.charAt(i))<=9&&Character.getNumericValue(s.charAt(i))>=0)
            {
                cd=1;
                
            
            
            
            
            }
            else if(s.charAt(i)<=90&&s.charAt(i)>=65)
            {
                cu=1;
            
            
            }
        else if(s.charAt(i)<=122&&s.charAt(i)>=97)
            {
                cl=1;
            
            
            }
        
        
        
        
        }
        
    
            count=cu+cl+cd+cs;
            int ad=4-count;
            
            if(n+ad<6)
            {
                ad=ad+(6-ad-n);
            
            
            }
        //System.out.println(cu);
        System.out.println(ad);
        
        
        
        
        
    
    
    
    
    
    }
    
}