B - Prime-partite Graph

We have a graph with $N$ nodes (numbered $1$ through $N$). For each valid $u$ and $v$, there is an undirected edge between nodes $u$ and $v$ if $v$ is a prime divisor of $u$ or $u$ is a prime divisor of $v$. You should answer $Q$ queries. In each query, you should find the length of the shortest path between two given nodes $a$ and $b$ or determine that there is no path between them. **Note**: B