Boss, I Can See You!#5613
— Oh, Boss, I can see you!
— Analogously!
From the animated film 'Investigation Held by Kolobki'
During their investigation, detectives Boss and Colleague got into an empty warehouse to look for evidence of crime. The warehouse is a polygon without self-intersections and self-tangencies, not necessarily convex. The detectives investigate the territory of warehouse in such a way that each of them can always see the other one. Boss and Colleague can see each other if all the points of a segment connecting them lie either inside the warehouse or on its border. Find the maximal possible distance between the detectives.
The first line contains an integer (3 \le n \le 200) of vertices of the polygon. Next lines contain two integers x_i, y_i each: coordinates of vertices in clockwise or counterclockwise order (-1000 \le x_i, y_i \le 1000). It is guaranteed that polygon has neither self-intersections nor self-tangencies.
Output the maximal possible distance between Boss and Colleague. The answer must be given with absolute or relative error not exceeding 10^{-6}.
Example 1