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单点时限: 15.0 sec
内存限制: 256 MB
Given a positive integer, your job is writing a program to determine whether it is a prime number or not.
There are thousands of tests. Each test consists of a positive integer (no more than ) on a single line. Input is terminated by end of file.
For each integer in the input, print a
YES if it is a prime number, otherwise print a
4 5 6
NO YES NO