milestone 5 : goal reached when tasks 2, 3 are complete.
For task 1 with priority 3 Rafik will have to eat some bread in 2 minutes, after tasks 3, 2, 15.
When task 1, 2, 3 are achieved Rafik can work 3 minutes with priority 4 on task 4 in order to Eat some bread.
task 1 : Rafik shall eat bread in 2 minutes, with priority 4, after task 3,2 and 15.