diff --git "a/0224LJH/202508/31 BOJ \353\271\204\354\212\267\355\225\234 \353\213\250\354\226\264.md" "b/0224LJH/202508/31 BOJ \353\271\204\354\212\267\355\225\234 \353\213\250\354\226\264.md"
new file mode 100644
index 00000000..b949e206
--- /dev/null
+++ "b/0224LJH/202508/31 BOJ \353\271\204\354\212\267\355\225\234 \353\213\250\354\226\264.md"	
@@ -0,0 +1,91 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+    static int size,ansIdx, longest=0;
+    static String ans1,ans2;
+    static String[] words;
+
+    static class TrieNode{
+        Map<Character, TrieNode> children = new HashMap<>();
+        String word;
+        int num;
+        boolean isWord;
+
+        public TrieNode(String word, int num){
+            this.word = word;
+            this.num = num;
+        }
+    }
+
+    static void insert(String nWord, int wordNum){
+        TrieNode node = root;
+        int len = 0;
+        int tempIdx = 0;
+        boolean isEnd = false;
+        String tempWord = "";
+
+        for (int i = 0; i < nWord.length(); i++){
+            Character c = nWord.charAt(i);
+            if (node.children.containsKey(c)){
+                node = node.children.get(c);
+                if (!isEnd){
+                    len++;
+                    tempWord = node.word;
+                    tempIdx = node.num;
+                }
+            } else {
+                node.children.put(c, new TrieNode(nWord,wordNum));
+                node = node.children.get(c);
+                isEnd = true;
+            }
+        }
+
+        if (longest < len || (longest == len && tempIdx < ansIdx )){
+            ansIdx = tempIdx;
+            longest = len;
+            ans1 = tempWord;
+            ans2 = nWord;
+        }
+    }
+
+    static TrieNode root = new TrieNode("",-1);
+
+    public static void main(String[] args) throws Exception {
+        init();
+        process();
+        print();
+
+    }
+
+    public static void init() throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        size =Integer.parseInt(br.readLine());
+        words = new String[size];
+        ansIdx = -1;
+        for (int i = 0; i < size; i++) {
+            words[i] = br.readLine();
+
+        }
+    }
+
+    public static void process(){
+        for(int i = 0; i < size; i++){
+            insert(words[i],i);
+//            System.out.println("longest = " + longest);
+//            System.out.println("ans1 = " + ans1);
+//            System.out.println("ans2 = " + ans2);
+        }
+    }
+
+    public static void print(){
+        System.out.println(longest);
+        System.out.println(ans1);
+        System.out.println(ans2);
+    }
+
+
+}
+```