@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Person)) return false;

        Person person = (Person) o;

        if (!firstName.equals(person.firstName)) return false;
        if (!mail.equals(person.mail)) return false;
        if (!phone.equals(person.phone)) return false;
        if (!secondName.equals(person.secondName)) return false;

        return true;
    }