There is a list of 'list of consecutive integers'. There could be a single integer as well.

Example list:

    list = {{2, 3, 4}, {3, 4, 5}, {3, 4, 5, 6}, {7}, {4, 5, 6, 7}}

Also given is the minimum and maximum integer of all lists combined (2,7) in above case.

Choosing one or more of above lists the aim is to maximize coverage in (2,7) without having a single repetition of any integer across all lists.

As an example, `{3,4,5,6,7}` seems to be the largest set of integers that can be obtained by selecting and joining sublists from `list` without introducing duplicates. How to obtain this set?