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
a=int(raw_input())
q=True

while(q):
    b=str(a)
    x=0
    if b == b[len(b)::-1]:
        for i in range(2,int(math.sqrt(a))):
            if a%i==0:
                break
            else :
                x+=1
        if( x== (int(math.sqrt(a)))-2):
            print a
            q=False
    a+=1