You are given the task of finding palindromic prime numbers.

An integer is said to be a palindrome if it is equal to its reverse. For example, 79197 and 324423 are palindromes.

In this challenge you will be given an integer N, 1 = N = 1000000.

You have to find the smallest integer M = N such that M is a prime number and M is a palindrome.

For example, if N is 64 then the answer is 101.

Input format

A single integer Non a single line.

Output format

Your output must consist of a single integer, the smallest prime palindrome greater than or equal to N.

Constraints

1 <= N <= 1000000