# Problem 55: Lychrel numbers
# If we take 47, reverse and add, 47 + 74 = 121, which is palindromic.
# Not all numbers produce palindromes so quickly. For example,
# 349 + 943 = 1292,
# 1292 + 2921 = 4213
# 4213 + 3124 = 7337
# That is, 349 took three iterations to arrive at a palindrome.
# Although no one has proved it yet, it is thought that some numbers, like 196, never produce a palindrome. A number that never forms a palindrome 
# through the reverse and add process is called a Lychrel number. Due to the theoretical nature of these numbers, and for the purpose of this 
# problem, we shall assume that a number is Lychrel until proven otherwise. In addition you are given that for every number below ten-thousand, it 
# will either (i) become a palindrome in less than fifty iterations, or, (ii) no one, with all the computing power that exists, has managed so far to 
# map it to a palindrome. In fact, 10677 is the first number to be shown to require over fifty iterations before producing a palindrome: 
# 4668731596684224866951378664 (53 iterations, 28-digits).
# Surprisingly, there are palindromic numbers that are themselves Lychrel numbers; the first example is 4994.
# How many Lychrel numbers are there below ten-thousand?
# NOTE: Wording was modified slightly on 24 April 2007 to emphasise the theoretical nature of Lychrel numbers.
def isPal(s):
  for i in range(len(s)//2+1):
    if s[i]!=s[-i-1]:
      return False
  return True
C = 0
for i in range(1,10000):
  C+=1
  n=i
  for j in range(50):
    n = n + int(''.join(str(n)[::-1]))
    if isPal(str(n)):
      C-=1
      break
print(C)