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
n = int(input())

data = []

for num in range(n):
    t = input()
    (l, r) = t.split(" ")
    l = int(l)
    r = int(r)
    data.append((l, r))

data = sorted(data, key = lambda s : s[1])

num = 1

ci = data[0]

for item in data:
    (il, ir) = item
    (cl, cr) = ci
    if (il > cr):
        ci = item
        num += 1

print(num)
