Transforming Data

Hi, I'm new to this Forum, I hope you can help me out.

I have data in the following form: There are patients in the rows, and different Therapies in the columns. in the cells there's the Duration of the therapy in months.

Patients Therapy 1 Therapy 2 Therapy 3
p1 10 4 5
p2 6 8
p3 9 7

I'd like to transorm it in a way where I have the Duration in the rows, and the number of patients that have a certain therapy in the cells (in month 0, a certain number of patients is in therapy 1).

Time Therapy 1 Therapy 2 therapy 3
Month 0 # of patients
Month 1
Month 2

I've also attached an Excel-file with two worksheets including the examples. Is it possible to transform the data in this way?

Thanks in advance!