old_contents: 
  n = int(input())
  liste=[]
  for i in range(n):
      j, d = [int(j) for j in input().split()]
      liste.append([j,j+d-1])
      
  liste.sort(key=lambda x: x[0])
  liste.sort(key=lambda x: x[1])
  
  J_max=0
  count=0
  
  for el in liste:
      if el[0]>J_max:
          J_max=el[1]
          count+=1
        
  print(count)
  
new_contents: '''
    Author Alumet 2015
    https://github.com/Alumet/Codingame
  '''
  
  n = int(input())
  liste=[]
  for i in range(n):
      j, d = [int(j) for j in input().split()]
      liste.append([j,j+d-1])
      
  liste.sort(key=lambda x: x[0])
  liste.sort(key=lambda x: x[1])
  
  J_max=0
  count=0
  
  for el in liste:
      if el[0]>J_max:
          J_max=el[1]
          count+=1
        
  print(count)
  
subject: Update Super_calculateur.py