Prime Substring

Given a string of digits, your task is to find the largest prime number which presents in that string. Our prime numbers are values between 2 to 100000 only.

Input

Each line contains a string of digits (255 digits at most). The line contains only 0 indicates the end which will not be processed. The input does not exceed 1000 lines.

Output

Print out in each line the largest prime number found in each input string.

Examples