The are N points on the plane (N is even). No three points belong to the same strait line.
Your task is to select two points in such a way, that strait line they belong to divides the set of points into two equalsized parts.
Input
First line contains one integer N (2 ≤ N ≤ 10000).
Each of next N lines contains pair of integers x_{i}, y_{i} (−10^{9} ≤ x_{i}, y_{i} ≤ 10^{9}), the coordinates of
ith point.
Output
Print the numbers of selected points.
Sample
input  output 

4
0 0
1 0
0 1
1 1
 1 4

Problem Author: Pavel Atnashev
Problem Source: USU Internal Contest, March 2002