# Arup Guha
# 12/15/2024
# Solution to Kattis Problem: Interval Scheduling
# https://open.kattis.com/problems/intervalscheduling

# Get number of items.
n = int(input())

# Store events here as [end, start]
events = []

# Read them.
for i in range(n):

    # Probably a way better way to do this...just storing in reverse order.
    toks = input().split()
    item = [0,0]
    item[0] = int(toks[1])
    item[1] = int(toks[0])
    events.append(item)

# Sort it
events.sort()

# Initial values.
res = 0
ready = -1

# Go through the events.
for i in range(n):

    # Room is free now, so schedule event i.
    if events[i][1] >= ready:
        res += 1

        # New time room will be ready.
        ready = events[i][0]

# Ta da!
print(res)