Let $p, q, r$ be distinct prime numbers and let 
\[ A = \{p^a q^b r^c \mid 0 \le a, b, c \le 5\} \]
Find the least $n \in \mathbb{N}$ such that for any $B \subset A$ where $|B| = n$, there exist elements $x$ and $y$ such that $x$ divides $y$.

Let's think step by step and output the final answer within \boxed{}.
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