GARDENHU  Garden Hull
We have a garden with trees in it. For each tree is represented by x and y coordinates. Your goal is to find the least amount of net needed to surround all the trees so that all trees are inside the net. In other words you need to find the the length of the convex hull around those points.
Input
On the first line a lonely integer N (3 <= N <= 10000) representing the number of trees in the garden. On each of the following N lines you will find two integers  the coordinates of the next tree.
Output
A single integer  the length of the convex hull. Round it up to an integer.
Example
Input: 4 0 0 5 0 1 1 0 5 Output: 17
hide comments
noble_mushtak:
20190909 01:27:32
I used round() instead of ceil() and I got the correct answer. Wording of the question is a bit ambiguous, but it means round to the nearest integer. 

gautams:
20150819 17:12:43
Question unclear... what to do with area if actual area comes to 17.55(for example)?? 

arunpatala:
20150801 10:13:12
so if rounding up, isnt the answer 18 

Haidar Abboud:
20140313 04:03:53
see BSHEEP 

VilimL:
20120621 11:57:51
"to round up" means "to get it rounded" 

~!(*(@*!@^&:
20090319 05:15:18
Thanks for a nice problem. It is very good for newbie.

Added by:  Nikola P Borisov 
Date:  20081124 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JSRHINO NODEJS PERL6 VB.NET 
Resource:  Fall Bulgarian National Contest 2003 