diff --git "a/Seol-JY/202512/13 BOJ G5 4\354\231\200 7.md" "b/Seol-JY/202512/13 BOJ G5 4\354\231\200 7.md"
new file mode 100644
index 00000000..d544b00a
--- /dev/null
+++ "b/Seol-JY/202512/13 BOJ G5 4\354\231\200 7.md"	
@@ -0,0 +1,24 @@
+```java
+import java.io.*;
+
+public class Main {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        long k = Long.parseLong(br.readLine().trim());
+        
+        long n = k + 1;
+        
+        StringBuilder sb = new StringBuilder();
+        while (n > 1) {
+            if (n % 2 == 0) {
+                sb.append('4');
+            } else {
+                sb.append('7');
+            }
+            n /= 2;
+        }
+        
+        System.out.println(sb.reverse().toString());
+    }
+}
+```