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 li and the finish time ri (li≤ri).
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.
The first line contains integer number n (1≤n≤5·105) − number of orders. The following n lines contain integer values li and ri each (1≤li≤ri≤109).
Print the maximal number of orders that can be accepted.
2
7 11
4 7
1
5
1 2
2 3
3 4
4 5
5 6
3
6
4 8
1 5
4 7
2 5
1 3
6 8
2