Show how the following Constraints can be represented in the model as below, please write the new Constraints for each condition.

1. The estimated finish date for a project has to be later than the start date.

2. A member of staff can only be a manager if of grade 3, 4 or 5.

3. Each member of staff must be either a member of a project team or a manager of a team.

4. No members of staff can be both a manager of any project team and a member of any project team.