You are grouping groups of 2. You should only be grouping 3 or more consecutive numbers. Also, you are not sorting the list, so it will fail on unordered lists.
The problem states that the list will always go in increasing order
OK, I see now.
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You are grouping groups of 2. You should only be grouping 3 or more consecutive numbers.
Also, you are not sorting the list, so it will fail on unordered lists.
The problem states that the list will always go in increasing order
OK, I see now.