

 Task: Dextrogyrate camelByteotia consists of N oasis in the desert, no three of which are collinear. Byteasar lives in one of these oasis and moreover he has an acquaintance in every other. Byteasar wants to pay a visit to as many of them as possible. He plans to travel on the back of his camel. The camel is as obstinate as a mule and thus moves in its own peculiar way:
Byteasar's camel is initially facing a certain oasis and it has to start moving toward it. The direction the camel faces after returning from the journey is of no importance. TaskWrite a programme that:
InputIn the first line of the standard input there is one integer N ( 3 <= N <= 1 000)  the number of oasis in Byteotia. The oasis are numbered from 1 to N. Byteasar lives in the oasis no. 1 and his camel is facing the oasis no. 2. In the following N lines the coordinates of the oasis are given. In the (i + 1)th line there are two integers x_{i}, y_{i}  the horizontal and vertical coordinate of the ith oasis  separated by a single space. All coordinates are from the interval from 16 000 to 16 000.
OutputIn the first and only line of the standard output your programme should write one integer  the maximum number of friends Byteasar can visit.
ExampleFor the following input data:6 1 1 1 4 0 1 4 1 0 3 1 4the correct answer is: 4 Print friendly version 