fix hd txt

Week 2.md

@@ -10,7 +10,7 @@ Original Array : [25, 14, 56, 15, 36, 56, 77, 18, 29, 49]
 New Array: [25, 14, 5, 56, 15, 36, 56, 77, 18, 29] 
 ```
 
-### Problem 3
+### Problem 2
 
 Write a Java program to remove a specific element(by index) from an array.