#!/bin/python3

import sys
numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"
def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    a=0
    
    for i in password:
        if i in numbers:
            a+=1
            break
    for i in password:
        if i in lower_case:
            a+=1
            break
    for i in password:
        if i in upper_case:
            a+=1
            break
    for i in password:
        if i in special_characters:
            a+=1
            break
    if n>5:
        return 4-a
    else:
        """return 4-a+6-n"""
        if 4-a==0:
            return 6-n
        if 4-a==1:
            if 4-a > 6-n:
                return 4-a
            else:
                return 6-n
        if 4-a==2:
            if 4-a > 6-n:
                return 4-a
            else:
                return 6-n
        if 4-a==3:
            if 4-a > 6-n:
                return 4-a
            else:
                return 6-n
        if 4-a==4:
            if 4-a > 6-n:
                return 4-a
            else:
                return 6-n
        
    
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)