Three Operations

Palermo along with other heist members is given an integer sequence of length $N$ which is $[a_1, a_2, ...., a_n]$. You are also given an integer $K$. For each $a_i$ $[1 \leq i \leq N]$, you can perform *any one* of the following operations: - Add $K$ to $a_i$, or - Subtract $K$ from $a_i$, or - Do nothing (keep the element unchanged). After these operations, you select a number $Y$ and find