diff --git a/day1/src/main.rs b/day1/src/main.rs
index a061ad2..1a933b7 100644
--- a/day1/src/main.rs
+++ b/day1/src/main.rs
@@ -1,10 +1,12 @@
-fn fuel_for_modules1(input: &str) -> i64 {
-	let mut fuel: i64 = 0;
-	for module in input.split_whitespace() {
-		let module: i64 = module.parse().unwrap();
-		fuel += (module / 3) - 2;
-	}
-	fuel
+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 {
@@ -13,17 +15,15 @@ fn fuel_for_mass2(mass: u64) -> u64 {
 	fuel + fuel_for_mass2(fuel)
 }
 
-fn fuel_for_modules2(input: &str) -> u64 {
-	let mut fuel: u64 = 0;
-	for module in input.split_whitespace() {
-		let module: u64 = module.parse().unwrap();
-		fuel += fuel_for_mass2(module);
-	}
-	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");
-	println!("Fuel 1: {}", fuel_for_modules1(input));
+	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));
 }