diff --git a/lkhyun/202509/17 BOJ G5 Fly me to the Alpha Centauri.md b/lkhyun/202509/17 BOJ G5 Fly me to the Alpha Centauri.md
new file mode 100644
index 00000000..58c2cd92
--- /dev/null
+++ b/lkhyun/202509/17 BOJ G5 Fly me to the Alpha Centauri.md	
@@ -0,0 +1,40 @@
+```java
+import java.util.*;
+import java.io.*;
+
+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 StringBuilder sb = new StringBuilder();
+    
+    public static void main(String[] args) throws Exception {
+        int T = Integer.parseInt(br.readLine());
+
+        for (int i = 0; i < T; i++) {
+            st = new StringTokenizer(br.readLine());
+            int x = Integer.parseInt(st.nextToken());
+            int y = Integer.parseInt(st.nextToken());
+            int diff = (y-x);
+            int cnt = 1;
+
+
+            double candidate = Math.sqrt(diff);
+            int temp = (int)candidate;
+            if(candidate*candidate == temp*temp) {
+                bw.write((temp*2 - 1)+"\n");
+                continue;
+            }else{
+                cnt = temp;
+            }
+                        
+            int rest = diff - cnt*cnt;
+            if(rest>cnt) bw.write((cnt*2 + 1) + "\n");
+            else bw.write((cnt*2)+"\n");
+        }
+        
+        bw.close();
+    }
+
+}
+```