diff --git "a/0224LJH/202507/21 BOJ \354\206\214\353\254\270\353\202\234 \354\271\240\352\263\265\354\243\274 .md" "b/0224LJH/202507/21 BOJ \354\206\214\353\254\270\353\202\234 \354\271\240\352\263\265\354\243\274 .md"
new file mode 100644
index 00000000..e8bcaed5
--- /dev/null
+++ "b/0224LJH/202507/21 BOJ \354\206\214\353\254\270\353\202\234 \354\271\240\352\263\265\354\243\274 .md"	
@@ -0,0 +1,107 @@
+```java
+import java.awt.*;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.HashSet;
+import java.util.Set;
+
+
+public class Main {
+    static String[][] arr = new String[5][5];
+    static Set<Point> set = new HashSet<>();
+    static HashSet<Point> temp = new HashSet<>();
+    static int[] dy = { -1,0,1,0};
+    static int[] dx = { 0,1,0,-1};
+    static int ans = 0;
+
+
+    public static void main(String[] args) throws IOException {
+        init();
+        process();
+        print();
+    }
+
+    private static void init() throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        for (int i = 0; i < 5; i++) {
+            arr[i] = br.readLine().split("");
+        }
+    }
+
+    private static void process() throws IOException {
+        combination(0,0);
+    }
+
+    private static void combination(int num, int idx) {
+        if ( idx == 7) {
+            check();
+            return;
+        }
+
+        for (int i = num; i < 25; i++){
+            int y = i/5;
+            int x = i%5;
+
+            set.add(new Point(x, y));
+            combination(i+1, idx+1);
+            set.remove(new Point(x, y));
+        }
+    }
+
+    private static void check() {
+
+
+        Point first = set.iterator().next();
+
+        int sCount = 0;
+        for (Point p : set) {
+            if(arr[p.y][p.x].equals("S") ) sCount++;
+        }
+
+
+        if (sCount >= 4 && checkConnected(first)) {
+            ans++;
+        }
+
+    }
+
+    private static boolean checkConnected(Point first) {
+        temp = new HashSet<>();
+        temp.add(first);
+
+        for (int i = 0 ; i < 7; i++){
+            for (Point p : set) {
+                if (temp.contains(p)) continue;
+
+                boolean isConnected = false;
+                for (int j = 0; j <4 ; j++){
+                    int ny = p.y + dy[j];
+                    int nx = p.x + dx[j];
+
+                    if (temp.contains(new Point(nx, ny))) {
+                        isConnected = true;
+                        break;
+                    }
+                }
+
+                if (isConnected) {
+                    temp.add(p);
+                }
+            }
+        }
+
+        return temp.size() == 7;
+
+    }
+
+
+    private static void print()  {
+        System.out.println(ans);
+    }
+
+
+
+}
+
+```
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