diff --git "a/lkhyun/202505/04 BOJ G4 \352\261\260\354\247\223\353\247\220.md" "b/lkhyun/202505/04 BOJ G4 \352\261\260\354\247\223\353\247\220.md"
new file mode 100644
index 00000000..b73e15a6
--- /dev/null
+++ "b/lkhyun/202505/04 BOJ G4 \352\261\260\354\247\223\353\247\220.md"	
@@ -0,0 +1,66 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    static StringTokenizer st;
+    static int N,M;
+    static boolean[] knowingPeople;
+
+    public static void main(String[] args) throws Exception {
+        st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        M = Integer.parseInt(st.nextToken());
+
+        st = new StringTokenizer(br.readLine());
+        int temp = Integer.parseInt(st.nextToken());
+        knowingPeople = new boolean[N+1];
+        for (int i = 0; i < temp; i++) {
+            knowingPeople[Integer.parseInt(st.nextToken())] = true;
+        }
+
+        List<List<Integer>> party = new ArrayList<>();
+        for (int i = 0; i < M; i++) {
+            List<Integer> l = new ArrayList<>();
+            st = new StringTokenizer(br.readLine());
+            int num = Integer.parseInt(st.nextToken());
+            for (int j = 0; j < num; j++) {
+                int people = Integer.parseInt(st.nextToken());
+                l.add(people);
+            }
+            party.add(l);
+        }
+
+
+        int prev;
+        int curr = party.size();
+        do{
+            prev = curr;
+            curr = 0;
+            
+            for (int i = 0; i < party.size(); i++) {
+                boolean found = false;
+                for (int j = 0; j < party.get(i).size(); j++) {
+                    if(knowingPeople[party.get(i).get(j)]){
+                        found = true;
+                        break;
+                    }
+                }
+                if(found){
+                    for (int j = 0; j < party.get(i).size(); j++) {
+                        knowingPeople[party.get(i).get(j)] = true;
+                    }
+                    party.remove(i--);
+                }else{
+                    curr++;
+                }
+            }
+        }while(!party.isEmpty() && prev != curr);
+
+        bw.write(curr + "");
+        bw.close();
+    }
+}
+```