Next Palindrome

Given an integer x, your task is to compute the smallest palindromic number that is strictly greater than x. A number is called a palindrome if it reads the same forwards and backwards. For example, 121 and 1331 are palindromic numbers, while 123 is not.

You can think of a palindromic number mathematically as satisfying the condition:

\( n = \text{reverse}(n) \)

where reverse(n) is the number obtained by reversing the digits of n.

Your solution should read the input from stdin and write the output to stdout.

inputFormat

The input consists of a single line containing one integer x (0 \leq x < 10^{18}), representing the number from which you should find the next palindrome.

outputFormat

Output the smallest palindromic number that is strictly greater than x. The result should be printed on a single line.

123

131