...on we) can place a frog (in such a way that it satisfies his wish) at some blue point, then mark a circle around it; otherwise mark a cross at that point ( [b]Observation[/b] If a blue point is circled, then we cannot circle its neighbor. ...

If <math>a = \frac {1}{3}</math> then segment (colored by blue) is tangent to red curve (discriminant is zero), so we have two solutions ( ...\cdot \frac {AD + EF}{2} = BC \cdot (2 + \frac{3}{5}) \cdot \frac {h \cdot NT}{2} = BC \cdot \frac{13}{15} \cdot [KNT].</cmath> ...

| 839 || nt-blue || 1 || 29.670 || 29.670 ...