These are the original strings
[1, 4, 9, 16]
[9, 7, 4, 9, 11]
[1, 4, 9, 16, 9, 7, 4, 9, 11]
These are the modified strings
[1, 4, 9, 16, 9, 7, 4, 9, 11]
[11, 9, 4, 7, 9, 16, 9, 4, 1]
-2