diff --git a/pu2rile/README.md b/pu2rile/README.md
index fec575c..3ef787b 100644
--- a/pu2rile/README.md
+++ b/pu2rile/README.md
@@ -2,7 +2,7 @@
 
 | 차시 |    날짜    | 문제유형 | 링크 | 풀이 |
 |:----:|:---------:|:----:|:-----:|:----:|
-| 1차시 | 2024.03.24 |  DP  | [평범한 배낭](https://www.acmicpc.net/problem/12865)  | [#3](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/3#issue-2205834078)|
+| 1차시 | 2024.03.24 |  동적 프로그래밍  | [평범한 배낭](https://www.acmicpc.net/problem/12865)  | [#3](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/3#issue-2205834078)|
 | 2차시 | 2024.03.29 |  구현  | [OX퀴즈](https://www.acmicpc.net/problem/8958)  | [#6](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/6#issue-2214931034)|
 | 3차시 | 2024.04.02 |  문자열  | [크로아티아 알파벳](https://www.acmicpc.net/problem/8958)  | [#10](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/10#issue-2220631332)
 | 4차시 | 2024.04.08 |  스택  | [제로](https://www.acmicpc.net/problem/10773)  | [#15](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/15#issue-2229909173)
@@ -13,3 +13,4 @@
 | 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)
 | 11차시 | 2024.07.13 |  우선순위 큐  | [강의실](https://www.acmicpc.net/problem/1374)  | [#37](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/37#issue-2406937336)
+| 12차시 | 2024.07.23 |  동적 프로그래밍  | [1학년](https://www.acmicpc.net/problem/5557)  | [#40](https://github.com/AlgoLeadMe/AlgoLeadMe-10/pull/40)
diff --git "a/pu2rile/\353\217\231\354\240\201 \355\224\204\353\241\234\352\267\270\353\236\230\353\260\215/1\355\225\231\353\205\204.py" "b/pu2rile/\353\217\231\354\240\201 \355\224\204\353\241\234\352\267\270\353\236\230\353\260\215/1\355\225\231\353\205\204.py"
new file mode 100644
index 0000000..13cc18e
--- /dev/null
+++ "b/pu2rile/\353\217\231\354\240\201 \355\224\204\353\241\234\352\267\270\353\236\230\353\260\215/1\355\225\231\353\205\204.py"	
@@ -0,0 +1,20 @@
+n = int(input())
+nums = list(map(int, input().split()))
+
+# dp 테이블 초기화
+dp = [[0] * 21 for _ in range(n)] # 0 이상 20 이하인 숫자이므로 크기가 21인 배열
+
+# 첫 번째 숫자를 dp 테이블에 초기값으로 설정
+dp[0][nums[0]] = 1
+
+# dp 테이블 채우기
+for i in range(1, n - 1):
+    for j in range(21):
+        if dp[i - 1][j]:
+            if j + nums[i] <= 20: # 더하기
+                dp[i][j + nums[i]] += dp[i - 1][j]
+            if j - nums[i] >= 0: # 빼기
+                dp[i][j - nums[i]] += dp[i - 1][j]
+
+# 마지막 숫자를 목표 값으로 만들 수 있는 경우의 수 출력
+print(dp[n-2][nums[-1]])
\ No newline at end of file