diff --git a/binary-tree-maximum-path-sum/shinsj4653.py b/binary-tree-maximum-path-sum/shinsj4653.py
new file mode 100644
index 000000000..f2dd9f373
--- /dev/null
+++ b/binary-tree-maximum-path-sum/shinsj4653.py
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+"""
+[문제풀이]
+# Inputs
+
+# Outputs
+
+# Constraints
+
+# Ideas
+
+[회고]
+
+"""
+
+
diff --git a/graph-valid-tree/shinsj4653.py b/graph-valid-tree/shinsj4653.py
new file mode 100644
index 000000000..f2dd9f373
--- /dev/null
+++ b/graph-valid-tree/shinsj4653.py
@@ -0,0 +1,15 @@
+"""
+[문제풀이]
+# Inputs
+
+# Outputs
+
+# Constraints
+
+# Ideas
+
+[회고]
+
+"""
+
+
diff --git a/merge-intervals/shinsj4653.py b/merge-intervals/shinsj4653.py
new file mode 100644
index 000000000..f2dd9f373
--- /dev/null
+++ b/merge-intervals/shinsj4653.py
@@ -0,0 +1,15 @@
+"""
+[문제풀이]
+# Inputs
+
+# Outputs
+
+# Constraints
+
+# Ideas
+
+[회고]
+
+"""
+
+
diff --git a/missing-number/shinsj4653.py b/missing-number/shinsj4653.py
new file mode 100644
index 000000000..267dd8f58
--- /dev/null
+++ b/missing-number/shinsj4653.py
@@ -0,0 +1,49 @@
+"""
+[문제풀이]
+# Inputs
+nums -> n개의 중복되지 않는 숫자들 (0 ~ n)
+
+# Outputs
+유일하게 0 ~ n 범위에 포함되어 있지 않은 수
+
+# Constraints
+n == nums.length
+1 <= n <= 10^4
+0 <= nums[i] <= n
+All the numbers of nums are unique.
+
+
+# Ideas
+
+O(1) SC, O(n) TC로 할 수 있을까?
+-> 처음엔 당연히 사전 쓰면 되겠지했지만, O(1) SC가 안됨
+
+정렬도 nlogn..
+
+길이 : n
+0부터 n 까지 합 =>
+n = 3
+
+0 1 2 3 -> 6
+sum(nums) -> 4
+남은 수 : 2
+
+[회고]
+이게 맞네
+1부터 n 까지 합 공식 -> (n * (n + 1)) // 2
+
+"""
+
+
+class Solution:
+    def missingNumber(self, nums: List[int]) -> int:
+        n = len(nums)
+        s = sum(nums)
+
+        total_s = 0
+
+        for i in range(n + 1):
+            total_s += i
+
+        return total_s - s
+
diff --git a/reorder-list/shinsj4653.py b/reorder-list/shinsj4653.py
new file mode 100644
index 000000000..f2dd9f373
--- /dev/null
+++ b/reorder-list/shinsj4653.py
@@ -0,0 +1,15 @@
+"""
+[문제풀이]
+# Inputs
+
+# Outputs
+
+# Constraints
+
+# Ideas
+
+[회고]
+
+"""
+
+