diff --git "a/LiiNi-coder/202512/21 BOJ \354\230\245\354\203\201 \354\240\225\354\233\220 \352\276\270\353\257\270\352\270\260.md" "b/LiiNi-coder/202512/21 BOJ \354\230\245\354\203\201 \354\240\225\354\233\220 \352\276\270\353\257\270\352\270\260.md"
new file mode 100644
index 00000000..2decc688
--- /dev/null
+++ "b/LiiNi-coder/202512/21 BOJ \354\230\245\354\203\201 \354\240\225\354\233\220 \352\276\270\353\257\270\352\270\260.md"	
@@ -0,0 +1,26 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		int N = Integer.parseInt(br.readLine());
+		long answer = 0L;
+		
+		Deque<Integer> stack = new ArrayDeque<>();
+
+		for(int i = 0; i < N; i++){
+			int height = Integer.parseInt(br.readLine());
+			while(!stack.isEmpty() && stack.peekLast() <= height){
+				stack.pollLast();
+			}
+
+			answer += stack.size();
+			stack.offerLast(height);
+		}
+		System.out.println(answer);
+	}
+}
+
+```