perl, 119 bytes

Result

AC

Duration

493ms

Code [DL]

@a=`dd`=~/\d+/g;$a[$_]-=$a[$_+3]for 0..8;$\-=$a[$_]/6*($a[$p=++$_%3+3]*$a[$q=++$_%3+6]-$a[$p+3]*$a[$q-3])for 0..2;print

stdin

01 79 09
24 78 05
69 36 71
78 20 47

stdout

7861

stderr

0+1 records in
0+1 records out

strace