I need to create a total variable that will sum the code frequencies from each response variable.

I have q25_* which asks respondents to indicate which advice sources they use

There are 15 different response options and respondents may choose up to 15 answers.

The attached image represents how this data has been inputted to STATA

n = 100 for q25_O1 spread across codes 1 - 15
n = 76 for q25_O2 spread across codes 1 - 15 (76 out of the 100 respondents chose more than one answer)
etc...

I want to create a variable that sums each of the response codes for each of q25_* and this will generate a cumulative frequency, eg n = 100 + 76 + n3 + n4 etc... spread across response options 1 - 15

Is someone able to help with syntax to generate this variable?