1271 Friend
Submit solution
Points:
100
Time limit:
1.0s
Memory limit:
32M
Problem types
Allowed languages
C, C++, Java, Python
Description
Friendnumber is 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 nonnegative 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
Output
YES!
YES!
NO!
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