diff --git a/python/104_maximum_depth_of_binary_tree.py b/python/104_maximum_depth_of_binary_tree.py
new file mode 100644
index 0000000..06f9f84
--- /dev/null
+++ b/python/104_maximum_depth_of_binary_tree.py
@@ -0,0 +1,5 @@
+class Solution:
+    def maxDepth(self, root: Optional[TreeNode]) -> int:
+        if root is None:
+            return 0
+        return max(self.maxDepth(root.left), self.maxDepth(root.right)) + 1
diff --git a/python/118_pascals_triangle.py b/python/118_pascals_triangle.py
new file mode 100644
index 0000000..c763227
--- /dev/null
+++ b/python/118_pascals_triangle.py
@@ -0,0 +1,7 @@
+class Solution:
+    def generate(self, numRows: int) -> List[List[int]]:
+        rows = []
+        for i in range(1, numRows + 1):
+            row = [1 if j == 0 or j >= i - 1 else rows[i-2][j-1]+rows[i-2][j] for j in range(i)]
+            rows.append(row)
+        return rows
diff --git a/python/28_find_the_index_of_the_first_occurrence_in_a_string b/python/28_find_the_index_of_the_first_occurrence_in_a_string.py
similarity index 100%
rename from python/28_find_the_index_of_the_first_occurrence_in_a_string
rename to python/28_find_the_index_of_the_first_occurrence_in_a_string.py