diff --git a/day02-gen-problem/Cargo.toml b/day02-gen-problem/Cargo.toml
index fcd3a60..a16c49e 100644
--- a/day02-gen-problem/Cargo.toml
+++ b/day02-gen-problem/Cargo.toml
@@ -3,7 +3,9 @@ name = "day02-gen-problem"
 version = "0.1.0"
 edition = "2021"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[package.metadata.nix]
+build = true
+app = true
 
 [dependencies]
 rand = "0.8.5"
diff --git a/day03-gen-problem/Cargo.toml b/day03-gen-problem/Cargo.toml
index 2b78eb0..07c6c12 100644
--- a/day03-gen-problem/Cargo.toml
+++ b/day03-gen-problem/Cargo.toml
@@ -3,7 +3,9 @@ name = "day03-gen-problem"
 version = "0.1.0"
 edition = "2021"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[package.metadata.nix]
+build = true
+app = true
 
 [dependencies]
 clap = { version = "4.0.29", features = ["derive", "wrap_help"] }
diff --git a/day03-gen-problem/src/main.rs b/day03-gen-problem/src/main.rs
index b8eb210..5090748 100644
--- a/day03-gen-problem/src/main.rs
+++ b/day03-gen-problem/src/main.rs
@@ -39,7 +39,7 @@ struct Args {
 
 impl Args {
     pub fn half_line_range(&self) -> Range<usize> {
-        self.min_line..self.max_line
+        (self.min_line / 2)..(self.max_line / 2)
     }
 }