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Friend

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3491    Accepted Submission(s): 1818


Problem Description
Friend number are defined recursively as follows.
(1) numbers 1 and 2 are friend number;
(2) if a and b are friend numbers, so is ab+a+b;
(3) only the numbers defined in (1) and (2) are friend number.
Now your task is to judge whether an integer is a friend number.
 

Input
There are several lines in input, each line has a nunnegative integer a, 0<=a<=2^30.
 

Output
For the number a on each line of the input, if a is a friend number, output “YES!”, otherwise output “NO!”.
 

Sample Input
3 13121 12131
 

Sample Output
YES! YES! NO!
 

Source
 

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