#!/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
    nm=1
    lc=1
    uc=1
    sc=1
    for i in password:
        if i in numbers:
            nm=0
        elif i in lower_case:
            lc=0
        elif i in upper_case:
            uc=0
        elif i in special_characters:
            sc=0
    if n < 6:
        diff=6-n
    else:
        diff=0
    return max(diff,(nm+lc+uc+sc))

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