Both individuals and organizations working with arXivLabs have accepted and accepted our values of openness, community, excellence and user data protection. arXiv is committed to these values and only works with partners who comply with them. arXivLabs is a framework that allows employees to develop and share new arXiv functions directly on our website. Do you have an idea for a project that adds value to the arXiv community? Learn more about arXivLabs and how to get involved. In this paper, we begin with a study of the question of how necessary is this exit? Could there be a much simpler and more intuitive Las Vegas protocol that works at the scheduled time of the polynom? We will show that the exponential duration of the Ben-Or and Bracha algorithms is not a coincidence of their specific details, but an inevitable consequence of their general symmetry and round structure. We consider our result as a step in identifying the degree of complexity required for a polynom time algorithm in this configuration, as well as as a guide in the search for new effective algorithms. DISC 2011: Distributed Computing S. 348-362 Cite ace.