The senior classman tied the silk to a telephone post, and walked around the perimeter of the area containing the Frosh, drawing the silk taught so as to encircle all of them. He then returned to the telephone post. The senior classman used the minimum amount of silk necessary to encircle all the frosh plus one extra metre at each end to tie it.
You may assume that the telephone post is at coordinates (0,0), where the first dimension is North/South and the second dimension is East/West. The coordinates of the Frosh are given in metres relative to the post. There are no more than 1000 Frosh.
The input consists of a line specifying the number of Frosh, followed by one line per Frosh with two real numbers his or her position. The output consists of a single number - the length of silk in metres, to two decimal places.
4 1.0 1.0 -1.0 1.0 -1.0 -1.0 1.0 -1.0