Programmer Andrey is very lucky. The Governor-General of Jamaica invited him
to visit this wonderful island. The whole trip, including plenty of entertainment,
will be completely free for Andrey. He will only have to help the Jamaican
Ministry of Transport and write a small program.
The point is that the Jamaican government decided to construct
a new network of expressways, in order to boost the economic
growth of the country. Each two cities are to be connected
by a road going along a straight line. One road may connect several
cities if they lie on the same straight line.
Jamaican economists are sure that the new network will minimize
transportation expenses. In order to estimate the cost of the
project, it is required to determine the total length of the roads
to be constructed, and this is the job for Andrey.
The first line contains the number n of cities in Jamaica
(1 ≤ n ≤ 300). The next n lines contain the
coordinates of the cities. In each of these lines, there are two
integers xi and yi separated by a
space (0 ≤ xi, yi ≤ 10000).
There are no cities with coinciding coordinates.
Output the total length of the roads rounded to the nearest integer.
Problem Author: Andrey Demidov
Problem Source: ACM ICPC 2007–2008. NEERC. Eastern Subregion. Yekaterinburg, October 27, 2007