const INPUT_FILE: &str = "input";

fn main() {
    let input = std::fs::read_to_string(INPUT_FILE).expect("Reading input file");
    let mut left: Vec<u32> = vec![];
    let mut right: Vec<u32> = vec![];
    for line in input.lines() {
        let mut fields = line.split_whitespace();
        let e = "Wrong file format";
        left.push(fields.next().expect(e).parse().expect(e));
        right.push(fields.next().expect(e).parse().expect(e));
    }
    left.sort_unstable();
    right.sort_unstable();

    let mut distance: u32 = 0;
    for i in 0..left.len() {
        let l = left[i];
        let r = right[i];
        distance += if l >= r { l - r } else { r - l };
    }
    println!("Distance: {}", distance);
}