pub fn read_file(day: u8) -> String {
    let filename = format!("inputs/day{}", day);
    std::fs::read_to_string(filename).unwrap()
}

pub fn read_lines(day: u8) -> Vec<String> {
    read_file(day).split_terminator('\n')
                  .map(String::from)
                  .collect()
}