#!/bin/python

import sys

def minimumNumber(n, password):
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    
    haveNumber = False
    haveLower = False
    haveUpper = False
    haveSc = False
        
    for c in password: 
        if c in numbers: 
            haveNumber = True
        if c in lower_case: 
            haveLower = True
        if c in upper_case: 
            haveUpper = True
        if c in special_characters: 
            haveSc = True
    
    rtn = 0
    
    if not haveNumber: 
        rtn += 1
    if not haveLower: 
        rtn += 1
    if not haveUpper: 
        rtn += 1
    if not haveSc: 
        rtn += 1
    
    if n + rtn < 6: 
        rtn = 6 - n
    
    return rtn
    # 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