#!/bin/python3

import sys
import re

def minimumNumber(n, password):
    count = 0
    if not bool(re.search(r'[\!\@\#\$\%\^\&\*\(\)\-\+]', password)):
        count += 1
    if not bool(re.search(r'[\d]', password)):
        count += 1
    if not bool(re.search(r'[a-z]', password)):
        count += 1
    if not bool(re.search(r'[A-Z]', password)):
        count +=1
    if 6 - n > count:
        return 6 - n
    else:
        return count
    # Return the minimum number of characters to make the password strong
    
    # 6 length is at least .
    #It contains at least one digit.
    # It contains at least one lowercase English character.
    # It contains at least one uppercase English character.
    # It contains at least one special character. The special characters are: !@#$%^&*()-+

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