Let
be an integer. What is the maximum number of disjoint pairs of elements of the set
such that the sums of the different pairs are different integers not exceeding
?
%V0
Let $n \geq 1$ be an integer. What is the maximum number of disjoint pairs of elements of the set $\{ 1,2,\ldots , n \}$ such that the sums of the different pairs are different integers not exceeding $n$?
Školjka