Four integers are read from input and inserted into widthList. Complete the following tasks:

Assign widthIterator with widthList's ListIterator object.

Move widthIterator between the elements at index $2$ and index $3.$

Use widthList to insert value $-1$ at index $3.$

Ex: If the input is $21274239,$ then the output is:

List contains: $212742-139$ widthIterator is between $-1$ and $39.$