diff --git a/.DS_Store b/.DS_Store
new file mode 100644
index 0000000..097f6a0
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diff --git a/pu2rile/.DS_Store b/pu2rile/.DS_Store
new file mode 100644
index 0000000..b798810
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diff --git a/pu2rile/README.md b/pu2rile/README.md
index b3f5ec3..7d06827 100644
--- a/pu2rile/README.md
+++ b/pu2rile/README.md
@@ -10,4 +10,5 @@
 | 6차시 | 2024.05.10 |  그리디 알고리즘  | [ATM](https://www.acmicpc.net/problem/11399)  | [#25](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/25#issue-2289086909)
 | 7차시 | 2024.05.10 |  완전 탐색 알고리즘  | [영화감독 숌](https://www.acmicpc.net/problem/1436)  | [#26](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/25#issue-2289086909)
 | 8차시 | 2024.05.14 |  그리디 알고리즘  | [팔](https://www.acmicpc.net/problem/1105)  | [#28](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/28#issue-2295901384)
-| 9차시 | 2024.05.27 |  구현  | [오늘도 졌다](https://www.acmicpc.net/problem/14582)  | [#29](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/29#issue-2320060288)
\ No newline at end of file
+| 9차시 | 2024.05.27 |  구현  | [오늘도 졌다](https://www.acmicpc.net/problem/14582)  | [#29](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/29#issue-2320060288)
+| 10차시 | 2024.07.11 |  스택  | [화학식량](https://www.acmicpc.net/problem/2257)  | [#35](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/35#issue-2403173169)
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diff --git "a/pu2rile/\354\212\244\355\203\235/.DS_Store" "b/pu2rile/\354\212\244\355\203\235/.DS_Store"
new file mode 100644
index 0000000..efd16c2
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diff --git "a/pu2rile/\354\212\244\355\203\235/\355\231\224\355\225\231\354\213\235\353\237\211.py" "b/pu2rile/\354\212\244\355\203\235/\355\231\224\355\225\231\354\213\235\353\237\211.py"
new file mode 100644
index 0000000..e964f10
--- /dev/null
+++ "b/pu2rile/\354\212\244\355\203\235/\355\231\224\355\225\231\354\213\235\353\237\211.py"
@@ -0,0 +1,22 @@
+chemical = input()
+stack = []
+atomic = {'H':1, 'C':12, 'O':16} # 원자량 딕셔너리
+
+for c in chemical:
+  if c =='(': 
+    stack.append(c)
+  elif c == 'H' or c == 'C' or c == 'O':
+    stack.append(atomic[c]) # 입력받은 원자의 원자량을 스택에 추가
+  elif c == ')':
+    temp = 0 # 닫는 괄호를 만나면 temp 초기화
+    while True:
+      if stack[-1] == '(': # 스택의 top이 여는 괄호면
+        stack.pop() # 스택에서 여는 괄호를 삭제
+        stack.append(temp) # 스택에 temp 추가
+        break
+      else:
+        temp += stack.pop() # 여는 괄호 전까지의 스택 안의 모든 값을 temp에 저장
+  else: # c가 숫자라면
+    stack.append(stack.pop()*int(c)) # 스택의 top 값과 숫자를 곱하여 스택에 추가
+
+print(sum(stack))
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