A production line at V. J Sugumaran's machine shop has three stations. The first station can process a unit in 5 minutes. The second station has three identical machines, each of which can process a unit in 24 minutes each unit only needs to be processed on one of the three machines. The third station can process a unit in 7 minutes.

is the bottleneck station, with a bottleneck time of minutes per unit. Enter answer as whole number.