File to import contains 1000 rows of two five digit numbers with no delimiter apart from CR/LF

import re

with open('./Day1Data.txt') as Both:
    line = Both.readline()
    while line:
        line = Both.readline()
        L = list(filter(None, re.split('s+', line)))
        A = L[0]
        B = L[1]
        print('L[0]: ' + A + 't' + ' / ' + 'L[1]: ' + B + 'n')

Complains:

    A = L[0]
        ~^^^
IndexError: list index out of range. 

After following suggestions to move the readLine in the while loop to the end, it successfully peeled off a line at a time, split it so L contains an array of two values, then A & B are the two values pulled out separately. All good!

import re

with open('./Day1Data.txt') as Both:
    line = Both.readline()
    while line:
        L = list(filter(None, re.split('s+', line)))
        A = L[0].strip()
        B = L[1].strip()
        print('L[0]: ' + A + ' / ' + 'L[1]: ' + B + 'n')
        line = Both.readline()

Which worked, giving expected output

L[0]: 70055 / L[1]: 70208

L[0]: 50040 / L[1]: 21717

L[0]: 24733 / L[1]: 98815

L[0]: 32343 / L[1]: 36965

L[0]: 75319 / L[1]: 86047

L[0]: 99792 / L[1]: 57533

L[0]: 51677 / L[1]: 88962

L[0]: 69872 / L[1]: 53641

L[0]: 68258 / L[1]: 35233

L[0]: 72704 / L[1]: 20997

L[0]: 78327 / L[1]: 63698

L[0]: 62435 / L[1]: 56887

L[0]: 84014 / L[1]: 77208

L[0]: 51255 / L[1]: 53718