paygo which discourages members from considering acts that increase budget deficits. If both houses agree to the version reported by the conference committee, the bill passes, otherwise it fails. The Constitution specifies that a majority of members (a quorum) be present before doing business in each house. The rules of each house assume that a quorum is present unless a quorum call demonstrates the contrary and debate often continues despite the lack of a majority. Voting within Congress can take many forms, including systems using lights and bells and electronic voting. Both houses use voice voting to decide most matters in which members shout "aye" or "no" and the presiding officer announces the result. The Constitution requires a recorded vote if demanded by one-fifth of the members present or when voting to override a presidential veto. If the voice vote is unclear or if the matter is controversial, a recorded vote usually happens. The Senate uses roll-call voting, in which a clerk calls out the names of all the senators, each senator stating "aye" or "no" when their name is announced. In the Senate, the Vice President may cast the tie-breaking vote if present when the senators are equally divided. The House reserves roll-call votes for the most formal matters, as a roll call of all 435 representatives takes quite some time; normally, members vote by using an electronic device. In the case of a tie, the motion in question fails. Most votes in the House are done electronically, allowing members to vote yea or nay or present or open. Members insert a voting ID card and can change their votes during the last five minutes if they choose; in addition, paper ballots are used occasionally (yea indicated by green and nay by red). One member cannot cast a proxy vote for another. Congressional votes are recorded on an online database. After passage by both houses, a bill is enrolled and sent to the president for approval. The president may sign it making it law or veto it, perhaps returning it to Congress with the president's objections. A vetoed bill can still become law if each house of Congress votes to override the veto with a two-thirds majority. Finally, the president may do nothingneither signing nor vetoing the billand then the bill becomes law automatically after ten days (not counting Sundays) according to the Constitution. But if Congress is adjourned