Almost Prime Check

An integer is called almost prime if it has exactly three distinct divisors. It turns out that a number has exactly three distinct divisors if and only if it is the square of a prime number.

Your task is to determine whether a given integer k is almost prime. In other words, check if k can be written as p² where p is a prime number.

The answer should be YES if k is almost prime and NO otherwise.

Note: Please use the standard input (stdin) to read input and standard output (stdout) to print out your answer. If k is not the square of a prime, print NO.

inputFormat

The input consists of a single integer k (1 ≤ k ≤ 10¹²) provided on a single line.

outputFormat

Output a single line containing either YES if the number is almost prime, or NO otherwise.

4

YES