diff --git a/kjs254/README.md b/kjs254/README.md
index 36c9ab2..211f377 100644
--- a/kjs254/README.md
+++ b/kjs254/README.md
@@ -11,3 +11,4 @@
 | 9차시 | 2024.03.10 | 구현 | [뉴스 클러스터링](https://school.programmers.co.kr/learn/courses/30/lessons/17677) | [#33](https://github.com/AlgoLeadMe/AlgoLeadMe-7/pull/33) |
 | 10차시 | 2024.04.02 | 해시 | [전화번호 목록](https://school.programmers.co.kr/learn/courses/30/lessons/42577) | [#46](https://github.com/AlgoLeadMe/AlgoLeadMe-7/pull/46) |
 | 11차시 | 2024.04.05 | DFS | [타겟 넘버](https://school.programmers.co.kr/learn/courses/30/lessons/43165) | [#47](https://github.com/AlgoLeadMe/AlgoLeadMe-7/pull/47) |
+| 12차시 | 2024.04.11 | DFS | [안전지대](https://school.programmers.co.kr/learn/courses/30/lessons/120866) | [#50](https://github.com/AlgoLeadMe/AlgoLeadMe-7/pull/50) |
\ No newline at end of file
diff --git "a/kjs254/\352\265\254\355\230\204/\354\225\210\354\240\204\354\247\200\353\214\200.py" "b/kjs254/\352\265\254\355\230\204/\354\225\210\354\240\204\354\247\200\353\214\200.py"
new file mode 100644
index 0000000..75cc5d8
--- /dev/null
+++ "b/kjs254/\352\265\254\355\230\204/\354\225\210\354\240\204\354\247\200\353\214\200.py"
@@ -0,0 +1,17 @@
+def solution(board):
+    n = len(board)
+    for i in range(n):
+        board[i].insert(0,-1)
+        board[i].append(-1)
+    board.insert(0,[-1]*(n+2))
+    board.append([-1]*(n+2))
+    
+    for i in range(n+2):
+        for j in range(n+2):
+            
+            if board[i][j]==1:
+                for dx in (-1,0,1):
+                    for dy in (-1,0,1):
+                        board[i+dy][j+dx] = board[i+dy][j+dx]*2 -1
+    
+    return sum(board, []).count(0)
\ No newline at end of file