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
ne = int(raw_input())

def palindrome(num):
     return  num == num[::-1]

def prime(num):
    if num > 1:
        co =0
        # check for factors
        for i in range(2,int(math.sqrt(num))):
            if num%i==0:
                return False
        return True



if ne>=98690:
    print "1003001"
else:
    while True:
        if palindrome(str(ne)) and prime(ne):
           print ne
           break

        ne+=1