Using if substr to identify ICD-10 codes with alpha code

[PunkinSAS08]

I have a list of over 200 ICD-10 codes and was recommended to use the substr function in SAS to capture all of them ex format. S020XXA and S020XXB

I have seen examples where the substr function helps flag the first few characters but how do I use this function to also include the "A" and "B" at the end of my ICD-10 code? I have included some of the icd10 codes needed here for reference: 

S02101A

S02101B

S02102A

S02102B

S02109A

S02109B

S0210XA

S0210XB

S02110A

S02110B

S02111A

S02111B

S02112A

S02112B

S02113A

S02113B

S02118A

[Astounding · Accepted solution]

Here's an example of using SUBSTR to also check for "A" or "B" as the last character:

if /* some conditions */ and substr(icd10, length(icd10) in "A", "B");

Since you're specifically asking about the last character, I omitted any logic that would check the earlier characters.