Given this nest dictionary grab the word "hello".

Notes:

We have provided a dic object.
Iterate over it and return last index word for target which is hello.

Instructions:

Program should be written in file build.py
Function name should be solution.

Input

 Type:  Dictionary
 Value: {'a1': [4, 2, 7, ("hello")]}

Expected Output
```
  Type:  String
  Value: ("hello")
```