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 check_prime(num):
    temp=int(math.sqrt(num))+1
    for i in range(2,temp,1):
        if(num%i==0):
            return 0
    return 1
n=input()
while(1):
    if(str(n)==(str(n))[::-1]):
        if(check_prime(n)):
            print n
            break
    n+=1