## How to evaluate $\int_{S^2} \sin(\theta) d\theta \wedge d\phi$?

I’m kind of stuck here. I try to apply Stokes Theorem, so that $$\int_{S^2} \sin(\theta) d\theta \wedge d\phi = \int_{D^2} d(\sin(\theta) d\theta \wedge d\phi) = 0$$ which is not the answer?