write the code that takes a pos number and the biggest perfect square that is equal to or less than

any example of this is

9 is inputed then it should return

9 since 3**2 equals 9 <= 4**2 equals 16>9

or if 20 is inputed then it should return 16 since 4**2 equals 16 <= 20 but 5**2 euqals 25 > 20

it should return it this format of the examples