Nemotron-IMO-Bench 2026 C14

Starting with a finite list of distinct positive integers, we may replace any pair $n, n + 1$ (not necessarily adjacent in the list) by the single integer $n-2$, now allowing negatives and repeats in the list. We may also replace any pair $n, n + 4$ by $n - 1$. We may repeat these operations as many times as we wish. What is the most negative integer which can appear in a list?