COUNT IF TEXT- Change from Non-LARC to LARC Methods

Dear friends,

I have a spreadsheet that contains two columns: column A represents the patient contraceptive method when they arrive to the clinic and column B, the patient contraceptive methods when leaving the clinic. There are 8 contraceptive types:

IUD, implant (LARC)
Depo-Provera, Pill, patch, ring, none, other (Non-LARC)

My goal is to count the instances (frequency and %) where the patient went from Non-LARC to a LARC contraceptive method (C17, D17). for example: from ring to IUD. We should not count instances where it was LARC to LARC. for example. from IUD to implant. My initial strategy was to add a column first to count each instances of change (column C). and then count that. But if there is way to count this directly, it would be great. Either way would work

Please see the attached document. I really would appreciate any help on this.

BEst,
Marvin