221021_1.txt

#백준 1931번
import sys
n = int(sys.stdin.readline())
arr = [list(map(int, sys.stdin.readline().split())) for _ in range(n)]
answer = 1

arr.sort(key=lambda x:(x[1],x[0]))
a = arr.pop(0)

for i in arr:
    if i[0] >= a[1]:
        answer+=1
        a = i
    
print(answer)