Perfect Ranges

A pair of arrays $A$ and $B$, both of length $N$, are called perfect if it is possible to form an array $C$ of length $N$ satisfying the following conditions: - $C_i = A_i$ or $C_i = B_i$ for each $1 \le i \le N$ - $C_i < C_{i + 1}$ for each $1 \le i < N$ --- You are given $2$ arrays $A$ and $B$ of length $N$. It is guaranteed that each element from $1$ to $2 \cdot N$ either occurs once in $A$