local mod = 998244353
local mfl = math.floor
local function bmul(x, y)
  local x0, y0 = x % 31596, y % 31596
  local x1, y1 = mfl(x / 31596), mfl(y / 31596)
  return (x1 * y1 * 62863 + (x1 * y0 + x0 * y1) * 31596 + x0 * y0) % mod
end
local function badd(x, y)
  return (x + y) % mod
end

local function bsub(x, y)
  return x < y and x - y + mod or x - y
end
local function modpow(src, pow)
  local res = 1
  while 0 < pow do
    if pow % 2 == 1 then
      res = bmul(res, src)
      pow = pow - 1
    end
    src = bmul(src, src)
    pow = mfl(pow / 2)
  end
  return res
end

local n, k = io.read("*n", "*n")
local add, rm = {}, {}
local lim = 200010
for i = 1, lim do
  add[i], rm[i] = 0, 0
end
for i = 1, n do
  local l, r = io.read("*n", "*n")
  add[l] = add[l] + 1
  rm[r] = rm[r] + 1
end
local a = 1
local cur = 0
for i = 1, lim do
  cur = cur - rm[i]
  for j = 1, add[i] do
    local rem = k - cur
    if rem <= 0 then a = 0 break end
    a = bmul(a, rem % mod)
    cur = cur + 1
  end
  if a == 0 then break end
end
local tot = modpow(k % mod, n)
local ans = bsub(tot, a)
print(ans)