Result

AC

Duration

594ms

Code [DL]

<?php
for($x=[],$i=5;--$i;)$x=array_merge($x,fgetcsv(STDIN,9," "));for(;$i<9;)$a+=($i>5)*($x[$i]-=$x[$i+3])*($x[3-~$i%3]*$x[$t=~-$i%3]-$x[++$i%3]*$x[$t+3]);echo$a/6;

stdin

60 28 67
01 13 01
29 31 58
10 56 21

stdout

9217

stderr

PHP Notice:  Undefined offset: -1 in /volume/CODE on line 2
PHP Notice:  Undefined variable: a in /volume/CODE on line 2