n, t = read_line.split.map(&.to_i)
evs = Array.new(200002) { [] of Int32 }
ps = Array.new(n) do |i|
  l, r, p = read_line.split.map(&.to_i)
  evs[l] << i
  evs[r + 1] << i
  p.to_i64
end
on = Array.new(n, false)
dp = Array.new(400002, 0i64)
q = PriorityQueue(Tuple(Int64, Int32)).new(n)
evs.size.times do |i|
  evs[i].each do |pi|
    on[pi] = !on[pi]
    if on[pi]
      q.add({ps[pi], pi})
    end
  end
  while q.size > 0 && !on[q.top[1]]
    q.pop
  end
  if q.size > 0
    dp[i + t] = {dp[i + t], dp[i] + q.top[0]}.max
  end
  dp[i + 1] = {dp[i + 1], dp[i]}.max
end
puts dp.max

class PriorityQueue(T)
  def initialize(capacity : Int32)
    @elem = Array(T).new(capacity)
  end

  def initialize(list : Enumerable(T))
    @elem = list.to_a
    1.upto(size - 1) { |i| fixup(i) }
  end

  def size
    @elem.size
  end

  def add(v)
    @elem << v
    fixup(size - 1)
  end

  def top
    @elem[0]
  end

  def pop
    ret = @elem[0]
    last = @elem.pop
    if size > 0
      @elem[0] = last
      fixdown(0)
    end
    ret
  end

  def clear
    @elem.clear
  end

  def decrease_top(new_value : T)
    @elem[0] = new_value
    fixdown(0)
  end

  def to_s(io : IO)
    io << @elem
  end

  private def fixup(index : Int32)
    while index > 0
      parent = (index - 1) // 2
      break if @elem[parent] >= @elem[index]
      @elem[parent], @elem[index] = @elem[index], @elem[parent]
      index = parent
    end
  end

  private def fixdown(index : Int32)
    while true
      left = index * 2 + 1
      break if left >= size
      right = index * 2 + 2
      child = right >= size || @elem[left] > @elem[right] ? left : right
      if @elem[child] > @elem[index]
        @elem[child], @elem[index] = @elem[index], @elem[child]
        index = child
      else
        break
      end
    end
  end
end