Some segments are given on a line. What is the maximum number of segments can be selected so that no two of them intersects? The segments are considered open.

Input

First line contains the number of segments n (1 ≤ n ≤ 105). Next n lines describe the segments: i-th line contains two integers li and ri (1 ≤ li < ri ≤ 109) - the coordinates of segment's starting and ending point.

Output

Print the maximum number of non intersecting segments.