Hi Doctor, My Wife Is Pregnant. But This Time We

Hi Doctor,
My wife is pregnant. But this time we don't need this we have a small kid. Doctor her period time was last month 11 till month her period date is 11. But today is 21. We got the positive result in pregnancy test. Doctor my doubt is yesterday night she take mifeprin 200. My doubt is after taking mifeprine how many hours to take zitotec 200 and how much it take. Need take all the 4 tab or lesser number.