#!/bin/python

import sys

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

def minimumNumber(n, password):
    nums = False
    low = False
    up = False
    spec = False
    
    i = 0
    while i < n and not (nums and low and up and spec):
        if password[i] in numbers:
            nums = True
        if password[i] in lower_case:
            low = True
        if password[i] in upper_case:
            up = True
        if password[i] in special_characters:
            spec = True
        i += 1
    
    count = 0    
    if not nums:
        count += 1
    if not low:
        count += 1
    if not up:
        count += 1
    if not spec:
        count += 1

    if count + n < 6:
        return 6 - n
        
    return count
        
    # if not numbers, count +1
    # if not lower, count +1
    # if not spec, count +1
    # length >= 6

    # Return the minimum number of characters to make the password strong

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