"""
Problem:
A palindromic number reads the same both ways. The largest palindrome made from
the product of two 2-digit numbers is 9009 = 91 x 99.

Find the largest palindrome made from the product of two 3-digit numbers which
is less than N.
"""


def solution(n):
 """Returns the largest palindrome made from the product of two 3-digit
 numbers which is less than n.

 >>> solution(20000)
 19591
 >>> solution(30000)
 29992
 >>> solution(40000)
 39893
 """
 # fetches the next number
 for number in range(n - 1, 10000, -1):

 # converts number into string.
 strNumber = str(number)

 # checks whether 'strNumber' is a palindrome.
 if strNumber == strNumber[::-1]:

 divisor = 999

 # if 'number' is a product of two 3-digit numbers
 # then number is the answer otherwise fetch next number.
 while divisor != 99:
 if (number % divisor == 0) and (len(str(int(number / divisor))) == 3):
 return number
 divisor -= 1


if __name__ == "__main__":
 print(solution(int(input().strip())))