#!/usr/bin/env python3

from random import randrange
import sys

L = []
with open(sys.argv[1], 'r') as f:
    L = f.readlines()
L = [int(x.strip()) for x in L]
l = len(L)

# part 1
while True:
    i = randrange(l)
    j = randrange(l)
    if L[i] + L[j] == 2020:
        print(L[i] * L[j])
        break

# part 2
while True:
    i = randrange(l)
    j = randrange(l)
    k = randrange(l)
    m = randrange(l)
    if L[i] + L[j] + L[k] + L[m] == 2020:
        print(L[i] * L[j] * L[k] * L[m])
        break

## part 1
#for n in L:
#    for nn in L:
#        if n + nn == 2020:
#            print(n * nn)
#
## part 2
#for n in L:
#    for nn in L:
#        for nnn in L:
#            if n + nn + nnn == 2020:
#                print(n * nn * nnn)