calculating deadweight loss in international economics

I'm doing this assignment and I'm totally lost,

U.S. :

d= 200 -40p

s= 40 +40p

Rest of the world:

d= 160 -40p

s= 80 +40p

The U.S. govenment imposes a quota of 32 units on its imports. Calculate the magnitude of deadweight loss resulting from the quota under the assumption that the U.S. is a small open economy?

If anyone knows about this it would great if you could help me out!