diff --git a/2017/src/day09.clj b/2017/src/day09.clj
new file mode 100644
index 0000000..7147e84
--- /dev/null
+++ b/2017/src/day09.clj
@@ -0,0 +1,34 @@
+(ns day09
+  (:require [clojure.string :as str]
+            core
+            input-manager))
+
+(def input (input-manager/get-input-raw 2017 9))
+
+(defn sum-recursive-depths [s sum idx depth]
+  (if (>= idx (count s))
+    sum
+    (condp = (.charAt s idx)
+      \, (recur s sum (inc idx) depth)
+      \{ (recur s
+                (+ sum depth)
+                (inc idx)
+                (inc depth))
+      \} (recur s
+                sum
+                (inc idx)
+                (max (dec depth) 0)))))
+
+(defn exlam-canceler [s] (str/replace s #"!." ""))
+(def angle-bracket-regex #"<[^>]*>")
+
+(-> input
+    exlam-canceler
+    (str/replace angle-bracket-regex "")
+    (sum-recursive-depths 0 0 1))
+
+(->> input
+     exlam-canceler
+     (re-seq angle-bracket-regex)
+     (map #(- (count %) 2))
+     (reduce +))