<P> If after a Bill has been passed by one House and transmitted to the other House--</P> <P> (a) the Bill is rejected by the other House; or (b) the Houses have finally disagreed as to the amendments to be made in the Bill; or (c) more than six months elapse from the date of the reception of the Bill by the other House without the Bill being passed by it, the President may, unless the Bill has elapsed by reason of a dissolution of the House of the People, notify to the Houses by message if they are sitting or by public notification if they are not sitting, his intention to summon them to meet in a joint sitting for the purpose of deliberating and voting on the Bill </P> <P> However, in calculating period of six months, those days are not considered when house is prorogued or adjourned for more than 4 consecutive days . </P> <P> If the above conditions are satisfied, the President of India may summon joint sitting of both the houses of parliament . </P>

Who chairs joint session of two houses of parliament