class BIT:
    def __init__(self, n):
        self.n = n
        self.data = [0] * (n + 1)
    
    def sum(self, i):
        s = 0
        while i > 0:
            s = (s + self.data[i]) % MOD
            i -= i & -i
        return s
    
    def add(self, i, x):
        while i <= self.n:
            self.data[i] = (self.data[i] + x) % MOD
            i += i & -i

MOD = 998244353

def cnt(N, K):
    bit = BIT(N + 1)
    bit.add(1, 1)  
    
    for i in range(1, N + 1):
        val = (bit.sum(i) - bit.sum(max(0, i - K + 1)) + MOD) % MOD
        bit.add(i + 1, val)
    
    return bit.sum(N + 1)
N, K = map(int, input().split())
result = cnt(N, K)
print(result)