Restaurant

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.

Input

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).

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

inputFormat

Input

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).

outputFormat

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

样例

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

2

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