module kkk
  sub main()
    
    dim n as long = Integer.Parse(Console.ReadLine)
    dim x(n - 1) as long
    dim l(n - 1) as long
    dim xl
    dim cnt as long
    dim flg(n - 1) as boolean
    
    dim i as long
    dim k as long
   
    
    
    for i = 0 to n - 1
    xl = console.readline()
    xl = split(xl, " ")
    x(i) = xl(0)
    l(i) = xl(1)
  next
  
  if n = 1 then
    console.writeline(0)
    exit sub
    end if
  
    
  for i = 0 to n - 2
    if flg(i) = false then
  if x(i) + l(i) >= x(i + 1) - l(i + 1)then
    cnt = cnt + 1
      flg(i + 1) = true
        for k = i + 1 to n - 1
        if flg(k) = false then
          if x(i) + l(i) >= x(k) - l(k) then
            cnt = cnt + 1
            flg(k) = true
          end if
        end if
      next
        end if
      end if
    next
    
console.writeline(cnt + 1)
    
  end sub
end module