what is the molar mass of a gaseous organic compound with a density of 3.38 g/L at 40oC and a pressure of 1.97 atm?

Ok, I am little confused because I am not sure of where to plug in the density and the atm?

PM = (g/v)RT

1.97*M = 3.38*0.08206*(273+40)
Solve for M.