Gravar-mail: Crystal structure of 16-hy­droxy-4,4,10,13,14-penta­methyl-17-(6-methyl­hept-5-en-2-yl)-4,5,6,9,10,11,12,13,14,15,16,17-dodeca­hydro-1H-cyclo­penta­[a]phenanthren-3(2H)-one