A restaurant received n orders for the rental. Each rental order reserve the restaurant for a continuous period of time, the i-th order is characterized by two time values — the start time l_{i} and the finish time r_{i} (l_{i} ≤ r_{i}).

Restaurant management can accept and reject orders. What is the maximal number of orders the restaurant can accept?

No two accepted orders can intersect, i.e. they can't share even a moment of time. If one order ends in the moment other starts, they can't be accepted both.

-----Input-----

The first line contains integer number n (1 ≤ n ≤ 5·10^5) — number of orders. The following n lines contain integer values l_{i} and r_{i} each (1 ≤ l_{i} ≤ r_{i} ≤ 10^9).

-----Output-----

Print the maximal number of orders that can be accepted.

-----Examples-----

Input 2 7 11 4 7

Output 1

Input 5 1 2 2 3 3 4 4 5 5 6

Output 3

Input 6 4 8 1 5 4 7 2 5 1 3 6 8

Output 2