Two can become tamei from a corpse — one becomes tamei for seven days, and one becomes tamei until evening. Three can become tamei from a corpse — two [of them] become tamei for seven days, and one becomes tamei until evening. Four can become tamei from a corpse — three [of them] become tamei for seven days, and one becomes tamei until evening. How [do] two [become tamei]? A person who touches a corpse becomes tamei for seven days, and a person who touches him becomes tamei until evening.