set/p q=
for /f "tokens=1-12 delims=%q:~8,1% " %%a in ("%q%") do (set/a a=%%d-%%a
set/a b=%%e-%%b
set/a c=%%f-%%c
set/a d=%%g-%%a
set/a e=%%h-%%b
set/a f=%%i-%%c
set/a g=%%j-%%a
set/a h=%%k-%%b
set/a i=%%l-%%c)
set/a v=(a*e*i+b*f*g+c*d*h-a*h*f-b*i*d-c*g*e)/6
echo %v%