#!/bin/python3

import sys

def minimumNumber(n, password):
    # Return the minimum number of characters to make the password strong
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    
    c_n = 1
    l_n = 1
    u_n = 1
    s_n = 1
    
    length = n
    
    for s in password:
        if s in numbers and c_n == 1:
            c_n = 0
        elif s in lower_case and l_n == 1:
            l_n = 0
        elif s in upper_case and u_n == 1:
            u_n = 0
        elif s in special_characters and s_n == 1:
            s_n = 0
     
    req = c_n + u_n + l_n + s_n
    
    if length + req >= 6:
        return req
    else:
        return 6 - length

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