diff --git a/src/week2/forkTest/SayHelloFork.java b/src/week2/forkTest/SayHelloFork.java
index 7a08898..3266947 100644
--- a/src/week2/forkTest/SayHelloFork.java
+++ b/src/week2/forkTest/SayHelloFork.java
@@ -1,4 +1,7 @@
 package week2.forkTest;
 
 public class SayHelloFork {
+	public static void main(String[] args) {
+		System.out.println("Hello Fork!");
+	}
 }
diff --git a/src/week9/antCave/Main.java b/src/week9/antCave/Main.java
new file mode 100644
index 0000000..76f9aa4
--- /dev/null
+++ b/src/week9/antCave/Main.java
@@ -0,0 +1,105 @@
+package week9.antCave;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.PriorityQueue;
+import java.util.StringTokenizer;
+
+public class Main {
+	static class Node implements Comparable<Node> {
+		String word;
+		PriorityQueue<Node> child = new PriorityQueue<>();
+		boolean isLeaf;
+		
+		public Node() {	}
+		
+		public Node(String word) {
+			this.word = word;
+			this.isLeaf = true;
+		}
+
+		public PriorityQueue<Node> getChild() {
+			return child;
+		}
+		
+		public Node findChild(String str) {
+			for(Node n : child) {
+				if(n.word.compareTo(str) == 0) {
+					return n;
+				}
+			}
+			return null;
+		}
+
+		public void addChild(Node c) {
+			this.child.add(c);
+			this.isLeaf = false;
+		}
+
+		@Override
+		public int compareTo(Node o) {
+			return (this.word).compareTo(o.word);
+		}
+	}
+
+	static class Trie {
+		Node root;
+
+		Trie() {
+			root = new Node();
+		}
+		
+		void insert(String words[]) {
+			Node node = this.root;
+			for(int i = 0; i < words.length; i++) {
+				if(node.isLeaf) {
+					Node newNode = new Node(words[i]);
+					node.addChild(newNode);
+					node = newNode;
+				} else {
+					Node newNode = node.findChild(words[i]);
+					if(newNode != null) {
+						node = newNode;
+					} else {
+						newNode = new Node(words[i]);
+						node.addChild(newNode);
+						node = newNode;
+					}
+				}
+			}
+		}
+		
+		void print(int cnt, PriorityQueue<Node> child) {	// preorder traversal (cnt = depth)
+			while(!child.isEmpty()) {
+				Node n = child.poll();
+				for(int i = 0; i < cnt * 2; i++) {
+					System.out.print('-');
+				}
+				System.out.println(n.word);
+				if(!n.isLeaf) {
+					this.print(cnt + 1, n.getChild());
+				}
+			}
+		}
+	}
+
+	public static void main(String[] args) throws IOException {
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+		StringTokenizer st;
+		int N = Integer.parseInt(br.readLine()); // 정보의 개수
+
+		Trie trie = new Trie();
+		for (int i = 0; i < N; i++) {
+			st = new StringTokenizer(br.readLine());
+			int K = Integer.parseInt(st.nextToken());
+			String words[] = new String[K];
+			for(int j = 0; j < K; j++) {
+				words[j] = st.nextToken();
+			}
+			trie.insert(words);
+		}
+
+		trie.print(0, trie.root.getChild());
+	}
+}
\ No newline at end of file