diff --git a/set1/chal1/src/main.rs b/set1/chal1/src/main.rs
index cfeb3ed..fd6e8e9 100644
--- a/set1/chal1/src/main.rs
+++ b/set1/chal1/src/main.rs
@@ -103,17 +103,18 @@ fn main() {
                                String::from("42")];
   assert_eq!(hex_to_string(&test), "AB");
 
+  // Get command line argument
   let args: Vec<String> = env::args().collect();
   let input = &args[1];
-
   let char_vec: Vec<char> = input.chars().collect();
+
+  // Convert Vec<char> to Vec<String> with 2 hexadecimal chars
+  // ie: ['4','1','4','2'] => ["41", "42"]
   let hex_char = &char_vec
     .chunks(2)
     .map(|chunk| chunk.iter().collect::<String>())
     .collect::<Vec<_>>();
 
-  let input_str = hex_to_string(&hex_char);
-
   // Convert hex_char : Vec<String> into Vec<u8>
   // Warning: Panic if not base16
   // See this with .map_err if we need to improve :
@@ -123,6 +124,10 @@ fn main() {
     .map(|i| u8::from_str_radix(i, 16).unwrap())
     .collect();
 
+  // Convert Hexadecimal Vec<String> to String
+  // ie: ["41", "42"] => "AB"
+  let input_str = hex_to_string(&hex_char);
+
   let output = base64_encode(&hex);
 
   println!("→ Input string is « {} »", input);