fn fuel_for_mass1(mass: u64) -> u64 {
	mass / 3 - 2
}

fn fuel_for_modules1<I>(input: I) -> u64
where
	I: IntoIterator<Item = u64>,
{
	input.into_iter().map(fuel_for_mass1).sum()
}

fn fuel_for_mass2(mass: u64) -> u64 {
	if mass <= 8 { return 0; } /* wish really hard */
	let fuel = mass / 3 - 2;
	fuel + fuel_for_mass2(fuel)
}

fn fuel_for_modules2<I>(input: I) -> u64
where
	I: IntoIterator<Item = u64>,
{
	input.into_iter().map(fuel_for_mass2).sum()
}

fn main() {
	let input = include_str!("input.txt").split_whitespace().map(|s| s.parse::<u64>().unwrap());
	println!("Fuel 1: {}", fuel_for_modules1(input.clone()));
	println!("Fuel 2: {}", fuel_for_modules2(input));
}