PMP Certification Executing Questions Test 3

While sequencing project activities, the team defines that:
Activity A has a duration of three weeks.
Activity C, with a duration of four weeks, will start first.
Activity B, with a duration of two weeks, will start after the completion of activity A.
Activity D, with a duration of four weeks, will start with a lead time of one week upon completion of activity B.
Activity E, with a duration of five weeks, will start after the completion of activity C.
Activity F, with a duration of three weeks, will have a start-to-start dependency with activity E, with a lag time of three weeks.
What is the project's shortest possible duration?