text: #!/usr/bin/env python
  
  with open("input.txt") as file:
  	entries = list(sorted(map(int, file.readlines())))
  
  for i, e1 in enumerate(entries):
  	for j, e2 in enumerate(entries):
  		if i != j and e1 + e2 == 2020:
  			print(e1 * e2)
  			exit()
  