• 1960 friend

    Time Limit : 2000/1000 MS(Java/Others) | Memory Limit : 131072/65536 KB(Java/Others)

    Submits : 76 | Solved : 41

    Description

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

    Input

    There are several lines in input file,each line has a nonnegative interger a ,(a is no more than 2^30)

    Output

    For the number a on each line of the input file ,if a is a friend number ,output ‘YES!’,otherwise output ‘NO!’

    Sample Input

    3
    13121
    12131
    
    

    Sample Output

    YES!
    YES!
    NO!
    

    HINT


    Source

    HDU - 1719

    [ Top ] | [ Submit ] | [ Statistics ] | [ Standing ]