#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    l=n
    digit=0
    lower=0
    upper=0
    special=0
    for i in password:
        if i.isdigit():
            digit+=1
        elif i.islower():
            lower+=1
        elif i.isupper():
            upper+=1
        else:
            special+=1
    if not digit:
        l+=1
    if not upper:
        l+=1
    if not lower:
        l+=1
    if not special:
        l+=1
    if l<6:
        return l-n+6-l
    else:
        return l-n
            

if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)