PHP CODE QUESTION

Thank you

Create a PHP script which prints numbers starting from the one input on the form, down till zero. The numbers should be separated by spaces, but there shouldn't be a space after the last number (the zero, that is). If the input value is less than zero, print the text "The number has to be at least zero!". The form used is as follows:

Luku:

Example output: The number has to be at least zero