IMO Shortlist 1993 problem G3
Let triangle

be such that its circumradius is

Let

be the inradius of

and let

be the inradius of the orthic triangle

of triangle

Prove that
%V0
Let triangle $ABC$ be such that its circumradius is $R = 1.$ Let $r$ be the inradius of $ABC$ and let $p$ be the inradius of the orthic triangle $A'B'C'$ of triangle $ABC.$ Prove that $$p \leq 1 - \frac{1}{3 \cdot (1+r)^2}.$$
Source: Međunarodna matematička olimpijada, shortlist 1993