<?php
$program_a = 'echo A;E925Z9A;';
$program_b = 'echo B; zzzzzz;';
eval( $program_c = $program_a ^
$program_b );
echo PHP_EOL, 'a ^ b = ';
PD9waHAKCmVycm9yX3JlcG9ydGluZyggMCApOwoKJHByb2dyYW1fYSA9ICdlY2hvIEE7RTkyNVo5QTsnOwoKJHByb2dyYW1fYiA9ICdlY2hvIEI7IHp6enp6ejsnOwoKZXZhbCggJHByb2dyYW1fYSApOwoKZXZhbCggJHByb2dyYW1fYiApOwoKZXZhbCggJHByb2dyYW1fYyA9ICRwcm9ncmFtX2EgXiAkcHJvZ3JhbV9iICk7CgplY2hvIFBIUF9FT0wsICdhIF4gYiA9ICc7Cgp2YXJfZHVtcCggJHByb2dyYW1fYyApOw==