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.
输入解释
There are several lines in input, each line has a nunnegative integer a, 0<=a<=2^30.
输出解释
For the number a on each line of the input, if a is a friend number, output “YES!”, otherwise output “NO!”.