diff --git a/mix.exs b/mix.exs
index be0a0c3..81aa8ab 100644
--- a/mix.exs
+++ b/mix.exs
@@ -21,8 +21,7 @@ defmodule Aoc20.MixProject do
   # Run "mix help deps" to learn about dependencies.
   defp deps do
     [
-      # {:dep_from_hexpm, "~> 0.3.0"},
-      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+      {:exprof, "~> 0.2.3"}
     ]
   end
 end
diff --git a/mix.lock b/mix.lock
new file mode 100644
index 0000000..bc6fbea
--- /dev/null
+++ b/mix.lock
@@ -0,0 +1,4 @@
+%{
+  "exprintf": {:hex, :exprintf, "0.2.1", "b7e895dfb00520cfb7fc1671303b63b37dc3897c59be7cbf1ae62f766a8a0314", [:mix], [], "hexpm", "20a0e8c880be90e56a77fcc82533c5d60c643915c7ce0cc8aa1e06ed6001da28"},
+  "exprof": {:hex, :exprof, "0.2.3", "8d4d657d73fc0c9ef1e30b2f9207b26ccbd2aec2baf1ca43f0b6d244c841c9f8", [:mix], [{:exprintf, "~> 0.2", [hex: :exprintf, repo: "hexpm", optional: false]}], "hexpm", "040410c672e2403908f578fb1e203a178692bbcd61b11d3745912662532b1dad"},
+}