diff --git a/README.md b/README.md
index 1a3b26c..bd07a1e 100644
--- a/README.md
+++ b/README.md
@@ -27,4 +27,5 @@ Disclaimer: in these solutions, I optimize for speed to submit a valid answer to
 | [Day 18](https://adventofcode.com/2024/day/18) | ⭐ | ⭐ |
 | [Day 19](https://adventofcode.com/2024/day/19) | ⭐ | ⭐ |
 | [Day 20](https://adventofcode.com/2024/day/20) | ⭐ | ⭐ |
+| [Day 21](https://adventofcode.com/2024/day/21) | ⭐ | ⭐ |
 <!--- advent_readme_stars table --->