Y=`dd`.split;r,t,y,a,b,c,d,e,f,g,h,i=Y.map_with_index{|e,i|e.to_i-Y[i%3].to_i};p (a*e*i+b*f*g+c*d*h-a*h*f-b*i*d-c*g*e)/6