#!/bin/python3
numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"

import sys

def minimumNumber(n, password):
    number = False
    lower = False
    upper = False
    special = False
    
    for char in password:
        if (not number) and (char in numbers):
            number = True
            #print(number)
        if (not lower) and (char in lower_case):
            lower = True
            #print(lower)
        if (not upper) and (char in upper_case):
            upper = True
            #print(upper)
        if (not special) and (char in special_characters):
            special = True
            #print(special)
    bools = [number, lower, upper, special]
    #print(bools)
    missing = abs(sum(bools) - 4)
    
    return missing + max((6 - len(password) - missing), 0)

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