#!/bin/python3
"""
1 Its length is at least 6.
2 It contains at least one digit.
3 It contains at least one lowercase English character.
4 It contains at least one uppercase English character.
5 It contains at least one special character.
"""
numbers = "0123456789"
lower_case = "abcdefghijklmnopqrstuvwxyz"
upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
special_characters = "!@#$%^&*()-+"


import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    c2 = any(i in password for i in numbers)
    c3 = any(i in password for i in lower_case)
    c4 = any(i in password for i in upper_case)
    c5 = any(i in password for i in special_characters)
    
    c = sum(map(int, [c2, c3, c4, c5]))
    
    r = 4 - c
    
    if n + r < 6:
        r += 6 - n - r
    return r
    

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