Is It Symmetric

It is easy to see that a string of digits like 1234321 is symmetric with 4 being the central digit. However it is less obvious if we consider the string as a circular one and shift it to the left as 2343211. Your task is to write a program to check if a circular string is symmetric.

Your program must read test cases from standard input.
The input file consists of several test cases. Each case occupies a line which contains the string. Each string contains less than 100 digits.
The input is finished by a "#".

For each test case, your program must output to standard output. If the string is not symmetric, output "NO" in a line; else output "YES", followed by a space and the position of the center (the position index starts from 0). It is guaranteed that the length of the string is an odd number and the center is unique.

2112343
798
#

YES 5
NO

浙大计算机研究生保研复试上机考试-2011年