An integer is said to be a palindrome if it is equal to its
reverse.  For example, 79197 and 324423 are palindromes. In this task
you will be given an integer N, 1 ≤ N ≤ 1000000.  You must find
the smallest integer M ≥ N such that M is a prime number and M is a
palindrome.  
For example, if N is 31 then the answer is 101.

Input
A single integer N, (1 ≤ N ≤ 1000000), on a single line.

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

Example

Input:
31
Output:
101
import sys

def isPrime(val):
	for i  in range(2, val/2+1):
		if val%i == 0:
			return 0 #not prime
	return 1 #is prime

def isPalindrome(val):
	return val == val[::-1]

number = int(raw_input())
while(1):
	if isPalindrome(str(number)):
		if isPrime(number):
			print number
			sys.exit()
	number += 1