Do you know confetti? They are small discs of colored paper, and people throw them around during parties or festivals. Since people throw lots of confetti, they may end up stacked one on another, so there may be hidden ones underneath.
A handful of various sized confetti have been dropped on a table. Given their positions and sizes, can you tell us how many of them you can see?
The following figure represents the disc configuration for the first sample input, where the bottom disc is still visible.