and-reas-se

fn main() {
    let input_file = std::env::args().nth(1).expect("Input filename missing");
    let input = std::fs::read_to_string(input_file).expect("Error reading file");

    let numbers = input
        .lines()
        .next()
        .unwrap()
        .split(',')
        .map(|num| num.parse().expect("invalid number"))