set /P s= set /a a=%s:~0,2% set /a b=%s:~3,2% set /a c=%s:~6,2% set /a d=%s:~9,2% set /a e=%s:~12,2% set /a f=%s:~15,2% set /a g=%s:~18,2%-a set /a h=%s:~21,2%-b set /a i=%s:~24,2%-c set /a j=%s:~27,2%-a set /a k=%s:~30,2%-b set /a l=%s:~33,2%-c set /a z=((e-b)*(i*j-g*l)+(f-c)*(g*k-h*j)+(d-a)*(h*l-i*k))/6 echo %l%