Riemann–Roch theorem

Ok! So the Riemann–Roch theorem is a way of figuring out how many special shapes (called holomorphic curves) are in a certain area. It's like if you wanted to know how many circles are inside a square. We would first have to figure out the area of the square and then look at what shapes fit inside the square. Then, using this theorem, you can count how many circles, or other shapes, fit inside. It's like a puzzle!