P3111 [USACO14DEC] Cow Jog S

The cows are out exercising their hooves again! There are N cows jogging on an infinitely-long single-lane track (1

INPUT: (file cowjog.in) The first line of input contains the two integers N and T. The following N lines each contain the initial position and speed of a single cow. Position is a nonnegative integer and speed is a positive integer; both numbers are at most 1 billion. All cows start at distinct positions, and these will be given in increasing order in the input.

OUTPUT: (file cowjog.out) A single integer indicating how many groups remain after T minutes.