Answer:
The answer is 2.
Step-by-step explanation:
1- Suppose we have following array of ten integers: 5 3 8 9 1 7 0 2 6 4.
2- Before the last merge, the left half and the right half must be sorted. So it should be
1 3 5 8 9 0 2 4 6 7
Therefore the solution is 2.