<?php
$interval = date_diff($datetime1, $datetime2);
echo $interval->m + $interval->y * 12;
PD9waHAKCgkkZGF0ZXRpbWUxID0gZGF0ZV9jcmVhdGUoJzIwMTYtMTAtMTEnKTsKCSRkYXRldGltZTIgPSBkYXRlX2NyZWF0ZSgnMjAxOC0xMC0xMScpOwoJJGludGVydmFsID0gZGF0ZV9kaWZmKCRkYXRldGltZTEsICRkYXRldGltZTIpOwoJCgllY2hvICRpbnRlcnZhbC0+bSArICRpbnRlcnZhbC0+eSAqIDEyOw==