import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    static int minimumNumber(int n, String p) {
        // Return the minimum number of characters to make the password strong
        
        int count=0;
        
        String numbers = "0123456789";
        boolean nf=false;
        String lower_case = "abcdefghijklmnopqrstuvwxyz";
            boolean lf=false;
        String upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            boolean uf=false;
        String special_characters = "!@#$%^&*()-+";
            boolean sf=false;
        
        for(int i=0;i<n;i++){
            if(numbers.indexOf(p.charAt(i))>=0){
                nf=true;
            }
            if(lower_case.indexOf(p.charAt(i))>=0){
                lf=true;
            }
            
            if(upper_case.indexOf(p.charAt(i))>=0){
                uf=true;
            }
            
            if(special_characters.indexOf(p.charAt(i))>=0){
                sf=true;
            }
            
            
            
            
        }
        
        int c=0;
        
        if(nf==false){
            c++;
        }
        
        if(lf==false){
            c++;
        }
        
        if(uf==false){
            c++;
        }
        
        if(sf==false){
            c++;
        }
        
        if(n+c<6){
            c+= (6-(n+c));
        }
        
        return c;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        String password = in.next();
        int answer = minimumNumber(n, password);
        System.out.println(answer);
        in.close();
    }
}