N = gets.to_i
L = gets.to_i

xs = $stdin.read.split.map(&:to_i).reverse + [0]

begin
  ans = 0
  sum = 0
  cnt = 0
  for i in 0...xs.size do
    if i > 0 then
      raise "-1" if (xs[i-1] - xs[i]).abs >= L

      center = sum / cnt.to_f #重心
      ok = true
      ok &&= xs[i-1] < center && center < xs[i-1] + L
      ok &&= xs[i] < center && center < xs[i] + L
      ans += 1 unless ok
    end

    sum += xs[i] + L / 2.0
    cnt += 1
  end

  puts ans
rescue
  puts $!
end