Two male singers, Paul and Sam; two female singers, Rita and Mita; two male comedians, Topu and Wahed; and two female comedians, Kate and Lira, are the eight entertainers who are to perform at the National Theater on a certain night. Each entertainer is to perform alone and only once that night. The entertainers may perform in any order that conforms to the followings restrictions:

• The performances by singers and the performances by comedians must alternate throughout the evening.
• The first performance that evening must be by a female entertainer, and the second performance by a male entertainer.
• The final performance must be by a male singer.

[Dhaka Bank MTO-2011 : 2011]