Normal Blood Pressure

Problem Description

In the intensive care unit, a patient's blood pressure is measured once every hour. A measurement is called normal if the systolic pressure is between $90$ and $140$ (inclusive) and the diastolic pressure is between $60$ and $90$ (inclusive). Given several measurements of a patient, compute the longest number of consecutive hours during which the blood pressure stayed normal.

Input Format

The first line contains a positive integer $n$ ($n < 100$).

The following $n$ lines each contain two positive integers: the systolic and diastolic pressures of one measurement, separated by a single space.

Output Format

Output a single line containing the longest number of consecutive hours with normal blood pressure.

Sample Input

4
100 80
90 50
120 60
140 90

Sample Output

2