#!/usr/bin/env python3

import re
from collections import Counter


def email_check(email):
    if not type(email) is str:
        raise TypeError

    domain = ''
    name = ''

    # Splitting into name and domain
    dogrule = '^[a-z0-9"!,:._-]*@[a-z0-9_.-]+$'
    if re.search(dogrule, email):
        name, domain = email.split("@")
    else:
        return False

    # Domain checking
    if len(domain) < 3 or len(domain) > 256:
        return False

    blocks = domain.split(".")

    for block in blocks:
        if len(block) == 0:
            return False

        leftdashrule = '^[-][a-z0-9_-]*$'
        rightdashrule = '^[a-z0-9_-]*[-]$'

        if re.search(leftdashrule, block) or re.search(rightdashrule, block):
            return False

    # Username checking
    if len(name) > 128:
        return False

    dotrule = '\.\.'
    if re.search(dotrule, name):
        return False

    noquoterule = '^[a-z0-9._-]*$'
    inquoterule = '^[a-z0-9!,:._-]*$'

    if '"' in name:
        if Counter(name)['"'] % 2 == 1:
            return False
        blocks = name.split('"')
        for i in range(len(blocks)):
            if i % 2 == 0 and not re.search(noquoterule, blocks[i]):
                return False
            if i % 2 == 1 and not re.search(inquoterule, blocks[i]):
                return False
    else:
        if not re.search(noquoterule, name):
            return False

    return True

def main():
    correct = [
        'zmalchunz@gmail.com',
        'zm"a,l:c!h"unz@gmail.com',
        'zverev_a_s@mail.ru',
        'zve.rev_a_s@mail.ru',
        '@asdrgaerg-wae',
    ]
    incorrect = [
        'zma"lchunz@gmail.com',
        'zm"a,l:c!hunz@gmail.com',
        'zm"a,l":c!hunz@gmail.com',
        'zverev_a_s@.mail.ru',
        'zverev_a_s@mail.ru.',
        'zverev_a_s@mail..ru',
        'zverev_a_s@-mail-.ru',
        'zverev_a_s@-mail.ru',
        'zverev_a_s@mail-.ru',
        'zve..rev_a_s@mail.ru',
        'aaregawerga',
        'wsergwrg@sa',
    ]
    for mail in correct:
        email_check(mail)

    for mail in incorrect:
        email_check(mail)

if __name__ == "__main__":
    main()