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) {
        // Return the minimum number of characters to make the password strong
        String spchars ="!@#$%^&*()-+";
        int ans = 0;
        int f1=0,f2=0,f3=0,f4=0,f5=0;
        if(n>=6)
            f1=1;
        for(int i=0;i<n;i++){
            if(password.charAt(i) >='0'  && password.charAt(i) <='9')
                f2=1;
           if(password.charAt(i) >='a'  && password.charAt(i) <='z')
                f3=1;
            if(password.charAt(i) >='A'  && password.charAt(i) <='Z')
                f4=1;
            if(password.charAt(i) == '!' || password.charAt(i) == '@' || password.charAt(i) == '#' || password.charAt(i) == '$' || password.charAt(i) == '%' ||password.charAt(i) == '^' ||password.charAt(i) == '&' ||password.charAt(i) == '*' ||password.charAt(i) == '(' ||password.charAt(i) == ')' ||password.charAt(i) == '-'||password.charAt(i) == '+' )
                f5=1;
            if(f2==1 && f3==1 && f4==1 && f5==1)
                break;
        }
        int d = 0;
        if(f2==0)
               d++;
            if(f3==0)
               d++;
            if(f4==0)
               d++;
            if(f5==0)
               d++;
        if(f1==0){
           int c = 6 - n;
           
           
            if(c>=d)
                ans = c;
            else
                ans = c + (d-c);
        }
        else
        {
            ans = d;
        }
        return ans;
    }

    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();
    }
}