There are circles which their centers lie on the Ox axis. Given the coordinates of their centers and their radius, find the number of regions they create on the plane.
The input starts with a line containing a single integer – the number of circles. Each of the following lines
consist of two space separated integers and which denote the ’th circle’s -coordinate and its radius
respectively.
Print a single integer in a line, denoting the number of regions on the plane.