Consider a process described by the following flow diagram: Note that activities B and C can be performed simultaneously, as can activities E and F. However, Activities B and C must both be completed before Activity D begins; similarly, Activities E and F must be completed before Activity G begins. Activity flow times are listed above each activity. There are four resources currently assigned — R1, R2, R3, and R4 — and the required resources are listed below each activity. Compute the flow time of the process (in minutes). Note: You do not need to write the word 'minutes' in your answer. If your answer is 10 minutes, then simply input 10.数值题