import vk_api
from vk_api.longpoll import VkLongPoll, VkEventType

def main():

    login, password = 'login', 'password'
    vk_session = vk_api.VkApi(login, password)
    vk = vk_session.get_api()
    try:
        vk_session.auth()
    except vk_api.AuthError as error_msg:
        print(error_msg)
        return
    longpoll = VkLongPoll(vk_session)

    x = "Дикей"

    for event in longpoll.listen():
        if event.type == VkEventType.MESSAGE_NEW and event.from_chat:
         if event.text == x:
            vk.messages.send(
                random_id=(),
                chat_id=event.chat_id,
                message='Мявк.'
                )

        if event.type == VkEventType.MESSAGE_NEW and event.from_user:
         if event.text == x:
            vk.messages.send(
                random_id=(),
                user_id=event.user_id,
                message='Мявк..'
                )
while True:
    try:
     main()
    except:
     main()
    finally:
     main()

while True:
     try:
         main()
     except:
         main()