Let
and
be positive integers such that
Find the least number
for which it is possible to place
pawns on
squares of an
chessboard so that no column or row contains a block of
adjacent unoccupied squares.
%V0
Let $n$ and $k$ be positive integers such that $\frac{1}{2} n < k \leq \frac{2}{3} n.$ Find the least number $m$ for which it is possible to place $m$ pawns on $m$ squares of an $n \times n$ chessboard so that no column or row contains a block of $k$ adjacent unoccupied squares.
Školjka