Perfect Square Checker

Given a positive integer ( n ), determine whether it is a perfect square. A number is a perfect square if it can be expressed as ( k^2 ) for some integer ( k ). For example, 16 is a perfect square because ( 4^2 = 16 ), whereas 20 is not a perfect square. Your program should read the input from standard input (stdin) and write the result to standard output (stdout).

inputFormat

The input consists of a single line containing one positive integer ( n ).

outputFormat

Output a single line: "YES" if ( n ) is a perfect square, otherwise "NO".## sample

16

YES