Write a PHP program to create a new string from a given string. If the first or first two characters is 'a'

<?php
function test($s1)
 { 
            if (strlen($s1) == 1 && substr($s1, 0, 1) == "a")
            {
                $s1 = substr($s1, 1);
            }

            if (strlen($s1) > 1)
            {
                if (substr($s1, 1, 1) == "a")
                {
                    $s1 = substr($s1, 0, 1).substr($s1, 2);
                }

                if (substr($s1, 0, 1) == "a")
                {
                    $s1 = substr($s1, 1);
                }
            }

            return $s1;
 }

echo test("abcab") . "\n";
echo test("Python") . "\n";
echo test("aacda") . "\n";
echo test("jython") . "\n";

Sample Output: