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 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-dependency with activity E, with lag time of three weeks.
What is the project's shortest possible duration?