diff --git "a/khj20006/202507/23 BOJ P4 \354\247\201\354\202\254\352\260\201\355\230\225 \353\247\214\353\223\244\352\270\260.md" "b/khj20006/202507/23 BOJ P4 \354\247\201\354\202\254\352\260\201\355\230\225 \353\247\214\353\223\244\352\270\260.md"
new file mode 100644
index 00000000..9962f436
--- /dev/null
+++ "b/khj20006/202507/23 BOJ P4 \354\247\201\354\202\254\352\260\201\355\230\225 \353\247\214\353\223\244\352\270\260.md"	
@@ -0,0 +1,106 @@
+```java
+import java.util.*;
+import java.io.*;
+
+class IOController {
+    BufferedReader br;
+    BufferedWriter bw;
+    StringTokenizer st;
+
+    public IOController() {
+        br = new BufferedReader(new InputStreamReader(System.in));
+        bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        st = new StringTokenizer("");
+    }
+
+    String nextLine() throws Exception {
+        String line = br.readLine();
+        st = new StringTokenizer(line);
+        return line;
+    }
+
+    String nextToken() throws Exception {
+        while (!st.hasMoreTokens()) nextLine();
+        return st.nextToken();
+    }
+
+    int nextInt() throws Exception {
+        return Integer.parseInt(nextToken());
+    }
+
+    long nextLong() throws Exception {
+        return Long.parseLong(nextToken());
+    }
+
+    double nextDouble() throws Exception {
+        return Double.parseDouble(nextToken());
+    }
+
+    void close() throws Exception {
+        bw.flush();
+        bw.close();
+    }
+
+    void write(String content) throws Exception {
+        bw.write(content);
+    }
+
+}
+
+public class Main {
+
+    static IOController io;
+
+    //
+
+    static int N;
+    static int[] arr;
+    static boolean[][][][] dp;
+
+    public static void main(String[] args) throws Exception {
+
+        io = new IOController();
+
+        init();
+        solve();
+
+        io.close();
+
+    }
+
+    static void init() throws Exception {
+
+        N = io.nextInt();
+        arr = new int[N];
+        for(int i=0;i<N;i++) arr[i] = io.nextInt();
+        dp = new boolean[71][71][71][71];
+
+    }
+
+    static void solve() throws Exception {
+
+        dp[0][0][0][0] = true;
+        for(int i=0;i<N;i++) {
+            boolean[][][][] ndp = new boolean[71][71][71][71];
+            for(int a=0;a<=70;a++) for(int b=0;b<=70;b++) for(int c=0;c<=70;c++) for(int d=0;d<=70;d++) if(dp[a][b][c][d]){
+                if(a+arr[i] <= 70) ndp[a+arr[i]][b][c][d] = true;
+                if(b+arr[i] <= 70) ndp[a][b+arr[i]][c][d] = true;
+                if(c+arr[i] <= 70) ndp[a][b][c+arr[i]][d] = true;
+                if(d+arr[i] <= 70) ndp[a][b][c][d+arr[i]] = true;
+            }
+            for(int a=0;a<=70;a++) for(int b=0;b<=70;b++) for(int c=0;c<=70;c++) for(int d=0;d<=70;d++) {
+                ndp[a][b][c][d] |= dp[a][b][c][d];
+            }
+            dp = ndp;
+
+        }
+        int ans = -1;
+        for(int i=1;i<=70;i++) for(int j=1;j<=70;j++) {
+            if(dp[i][i][j][j]) ans = Math.max(ans, i*j);
+        }
+        io.write(ans + "\n");
+
+    }
+
+}
+```