local mod = 998244353
local function badd(x, y) return (x + y) % mod end
local n, k = io.read("*n", "*n")
local t = {1}
local tsum = {1}
for i = 2, n + 1 do
  local r = i - k
  if 1 <= r then
    t[i] = tsum[r]
  else
    t[i] = 0
  end
  tsum[i] = badd(t[i], tsum[i - 1])
end
print(tsum[n + 1])