const val mod = 998244353

fun modpow(x: Long, n: Long ): Long {
    return when (n) {
        0L -> {
            1
        }
        1L -> {
            x
        }
        else -> {
            val tmp = modpow(x, n / 2)
            tmp * tmp % mod * (if (n % 2 == 1L) x else 1) % mod
        }
    }
}

fun main() {
    val (n, l) = readLine()!!.split(" ").map { it.toLong() }
    val beki = (n + l - 1) / l
    println((modpow(2,beki)+mod-1)%mod)
}