diff --git a/datastructure/src/main/java/org/alis/algorithm/leetcode/LeetCode17.java b/datastructure/src/main/java/org/alis/algorithm/leetcode/LeetCode17.java
index c526fa5..bc6695b 100644
--- a/datastructure/src/main/java/org/alis/algorithm/leetcode/LeetCode17.java
+++ b/datastructure/src/main/java/org/alis/algorithm/leetcode/LeetCode17.java
@@ -13,27 +13,10 @@ public class LeetCode17 {
         System.out.println(count);
     }
 
-    private static Integer advanced(Integer n) {
-
-        if (n == 1) {
-            return 1;
-        }
-
-        if (n == 2) {
-            return 2;
-        }
-
-        int a = 1;
-        int b = 2;
-        int temp = 0;
-
-        for (int i = 3; i <= n; i++) {
-            temp = a + b;
-            a=b;
-            b=temp;
-
+    private static int advanced(int n) {
+        if (n == 1 || n==2) {
+            return n;
         }
-        return temp;
+        return ladder(n - 1) + ladder(n - 2);
     }
-
 }
\ No newline at end of file