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 math
def isPrime(number):
	for x in xrange(2, int(math.sqrt(number))+1):
		if number%x == 0:
			return False
	return True
a = input()
for x in xrange(a, 10000000):
	isPal = False
	if str(x) == str(x)[::-1]:
		if isPrime(x):
			print(x)
			break;