# -*- coding: utf-8 -*-


s = input()
index = len(s)-9
total = 0
if s[:index] <= s[-index:]:
    total += 1
i = 1
left_numbers = s[:index]
while i < int(left_numbers):
    check_num = str(i)
    if check_num == check_num[::-1]:
        total += 1
    i += 1
print(total)