Niranjan goes 6 km towards East from Library, and takes a right turn. Now he goes 3 km and takes a left turn. He goes 6 km and takes a right turn. He again goes 3 km and takes a right turn. He now goes 6 km and takes a left turn. He now travels 3 km and takes a left turn to reach his home which is 6 km away. What is the shortest distance between library and Niranjan’s home?