Keep track of anything that you want to count like counting number of passenger on-board of this flight, number of bottle of wine you have been drinking since this month, number of night you slept after 12am and many many more ......
Keep track of anything that you want to count like counting number of passenger on-board of this flight, number of bottle of wine you have been drinking since this month, number of night you slept after 12am and many many more ......