Different Replacement

You're given an array $A$ of length $N$, with elements between $1$ and $N$. You will perform the following operation **exactly once**: - Choose two indices $L$ and $R$ ($1 \leq L \leq R \leq N$). - Then, choose an integer $X$ ($1 \leq X \leq N$) such that $X$ **does not appear** among $[A_L, A_{L+1}, A_{L+2}, \ldots, A_R]$. - Finally, for each $i$ from $L$ to $R$ (inclusive of both), set $A_i$ to