Get substring value with defined length using python

Question

I'd like to make a program in python to slice the string with length 23. I have a code that solves the purpose. I would like to know if there is a better and simple way to do this?

    prtNum = "88-90-25-65-13-20-20-41-88-90-25-65-13-20-20-41-88-91-31-81-81-20-20-44-88-91-31-81-82-20-20-44-88-91-31-82-81-20-20-44-88-91-31-81-83-20-20-44"
   len = len(prtNum)
   length = 23
   start = 0
    for i in range(0, len):
        sw = prtNum[start:length]
        len1 = length + 1
        start = len1
        length = length+ 24
        print(sw)

output looks like this:
   88-90-25-65-13-20-20-41
   88-90-25-65-13-20-20-41
   88-91-31-81-81-20-20-44
   88-91-31-81-82-20-20-44
   88-91-31-82-81-20-20-44
   88-91-31-81-83-20-20-44