diff --git a/missing-number/parkhojeong.py b/missing-number/parkhojeong.py
new file mode 100644
index 0000000000..a6b2c49213
--- /dev/null
+++ b/missing-number/parkhojeong.py
@@ -0,0 +1,15 @@
+class Solution:
+    def missingNumber(self, nums: List[int]) -> int:
+        N = max(nums)
+        num_set = set()
+
+        for i in range(N + 1):
+            num_set.add(i)
+
+        for num in nums:
+            num_set.remove(num)
+
+        if len(num_set) == 0:
+            return N + 1
+        else:
+            return num_set.pop()