from pprint import pprint

def search(l, key):
	for ix, x in enumerate(l):
		for iy, y in enumerate(l):
			if x == y:
				continue

			if x + y == key:
				return x, y

with open("sum.txt", "r", encoding="utf-8") as f:
	s = f.read()
ls = s.split()
l = [int(x) for x in ls]
x, y = search(l, 2020)
pprint((x, y))
print(x*y)