<?php
$data1 = '20-09-16';
$data2 = '23-09-16';
echo $dia1 = mktime( 0, 0, 0, $data1[1], $data1[0], 2000+$data1[2] ); echo $dia2 = mktime( 0, 0, 0, $data2[1], $data2[0], 2000+$data2[2] );
echo ( $dia2 - $dia1 ) / 86400;
PD9waHAKCiAgICAkZGF0YTEgPSAnMjAtMDktMTYnOwogICAgJGRhdGEyID0gJzIzLTA5LTE2JzsKICAgIAogICAgJGRhdGExID0gZXhwbG9kZSggJy0nLCAkZGF0YTEgKTsKICAgICRkYXRhMiA9IGV4cGxvZGUoICctJywgJGRhdGEyICk7CgogICAgZWNobyAkZGlhMSA9IG1rdGltZSggMCwgMCwgMCwgJGRhdGExWzFdLCAkZGF0YTFbMF0sIDIwMDArJGRhdGExWzJdICk7CiAgICBlY2hvICRkaWEyID0gbWt0aW1lKCAwLCAwLCAwLCAkZGF0YTJbMV0sICRkYXRhMlswXSwgMjAwMCskZGF0YTJbMl0gKTsKCiAgICBlY2hvICggJGRpYTIgLSAkZGlhMSApIC8gODY0MDA7