day_01a.py

#!/usr/bin/env python3


def main():
    total = 2020
    f = open("../input/day_01_input")
    numbers = set()
    for line in f:
        line = line.strip().replace("\n", "").replace("\r", "")
        num = int(line)
        diff = total - num
        if diff in numbers:
            print(diff * num)
            return diff * num
        else:
            numbers.add(num)
    return 0


if __name__ == "__main__":
    main()