24 подстрока в 14й

#24 https://kompege.ru/variant?kim=25097382
s = open('24_21908.txt').readline()
n = len(s)
fi_non0 = -1
alph = '1234567890ABCD'
chet = '02468AC'
answ = (0, 0) #число в десятичной и длина
for r in range(n):
    if s[r] in alph:
        if s[r] != '0' and fi_non0 == -1:
            fi_non0 = r
        if s[r] in chet and fi_non0 != -1:
            answ = max(answ, (int(s[fi_non0:r + 1], 14), r + 1 - fi_non0))
    else:
        fi_non0 = -1
print(answ[1])