Given is a square of sides $3\sqrt7 \times 3\sqrt7$. Find the minimal positive integer $n$ such that no matter how we put $n$ unit disks inside the given square, without overlapping, there exists a line that intersects $4$ disks.
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Tags: combinatorics, 5th edition
Given is a square of sides $3\sqrt7 \times 3\sqrt7$. Find the minimal positive integer $n$ such that no matter how we put $n$ unit disks inside the given square, without overlapping, there exists a line that intersects $4$ disks.