#!/usr/bin/env python
# 2024 - Advent Of Code 1

# file = 'input_example.txt'
file = 'input.txt'

firsts = []
seconds = []
accum = 0
with open(file, encoding="utf-8") as f:
    for line in f.readlines():
        a, b, c, d = line.strip().split(' ')
        firsts.append(int(a))
        seconds.append(int(d))

firsts.sort()
seconds.sort()

for x, y in zip(firsts, seconds):
    accum += abs(y - x)

print(f"sum: {accum}")