(3R,11aS)-2,3,3aβ,4,5,5a,5bα,6,6a,7,8,9,9aβ,10-Tetradecahydro-3β,5aα,6aα-trimethyl-9β-isopropyl-1H-pentaleno[1,6a-a]-s-indacene-11-carboxylic acid