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 password) {
    char ch;
    int capitalFlag = 0;
    int lowerCaseFlag = 0;
    int numberFlag = 0;
    int specialFlag = 0;
    int sum = 0;
    int add = 0;
    int x = 0;
    for(int i=0;i < password.length();i++) {
        ch = password.charAt(i);
        if( Character.isDigit(ch)) {
            numberFlag++;
        }
        else if (Character.isUpperCase(ch)) {
            capitalFlag++;
        } 
        else if (Character.isLowerCase(ch)) {
            lowerCaseFlag++;
        }
        else
            specialFlag++;
    }
    if(numberFlag>=1)
        numberFlag += 0;
    else{
        numberFlag += 1;
        add++;
    }    
    if(capitalFlag>=1)
        capitalFlag += 0;
    else{
        capitalFlag += 1;
        add++;
    }    
        
    if(lowerCaseFlag>=1)
        lowerCaseFlag += 0;
    else{
        lowerCaseFlag += 1;
        add++;
    }    
       
    if(specialFlag>=1)
        specialFlag += 0;
    else{
        specialFlag += 1;
        add++;
    }    
       
       sum = numberFlag+capitalFlag+lowerCaseFlag+specialFlag;
       if(sum>=6)
           return add;
       else{
           x = 6 - sum;
           return(add+x);
       }
           
   }

    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();
    }
}