#!/bin/python

import sys

def minimumNumber(n, password):
    if not password :
        return 6
    lenP = len(password)
    #declaring cases
    numbers = "0123456789"
    lower_case = "abcdefghijklmnopqrstuvwxyz"
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    special_characters = "!@#$%^&*()-+"
    nFlag = 1
    lFlag = 1
    uFlag = 1
    sFlag = 1
    for i in range(lenP) :
        if password[i] in numbers :
            nFlag = 0
        if password[i] in lower_case :
            lFlag = 0
        if password[i] in upper_case :
            uFlag = 0
        if password[i] in special_characters :
            sFlag = 0
    #calculating the remaining bits 
    #residual bits 
    resVal = nFlag + lFlag + uFlag + sFlag
    if lenP > 6 :
        return resVal
    else :
        return max((6-lenP),resVal)
    

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