#!/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 = "!@#$%^&*()-+"
    cnums=1; clc =1; cuc = 1; csc = 1; 
    for letter in password:
        #print(letter)
        if letter in lower_case:
            clc-=1
        elif letter in upper_case:
            cuc-=1
        elif letter in special_characters:
            csc -=1
        else:
            cnums-=1
    #print(clc,cuc,csc, cnums)
    temp = len(password)+max(0,clc)+max(0,cuc)+max(0,csc)+max(0,cnums)
    if temp<6:
        return 6 - len(password)
    else:
        return temp-len(password)
if __name__ == "__main__":
    n = int(input().strip())
    password = input().strip()
    answer = minimumNumber(n, password)
    print(answer)