# 入力
N, K = map(int, input().split())

# 二項係数の計算 O(K^2)
comb = [[0] * (K + 1) for i in range(K + 1)]
for i in range(K + 1):
    comb[i][0] = 1
    for j in range(1, i + 1):
        comb[i][j] = (comb[i - 1][j - 1] + comb[i - 1][j]) % 998244353

# 行列累乗の答えを保持する変数　初期値は
# [ (F[1]^K)*(F[0]^0), (F[1]^(K-1))*(F[0]^1), ... , (F[1]^0)*(F[0]^K), 0 ]
r = [1] * (K + 2)
r[K + 1] = 0

# 二項係数と0からなる行列(解説を参照)
# 最後の行はS[i-1]からS[i]を求めるためのもの
p = [[0] * (K + 2) for i in range(K + 2)]
for i in range(K + 1):
    for j in range(K + 1 - i):
        p[i][j] = comb[K - i][K - i - j]
p[K + 1][K] = 1
p[K + 1][K + 1] = 1

# 行列累乗 O(K^3 log N)
while N != 0:
    if N % 2 == 1:
        # r *= p の計算 O(K^2)
        tmp = [0] * (K + 2)
        for i in range(K + 2):
            for j in range(K + 2):
                tmp[i] = (tmp[i] + r[j] * p[i][j]) % 998244353
        r = tmp
    N //= 2
    # p *= p の計算 O(K^3)
    tmp = [[0] * (K + 2) for i in range(K + 2)]
    for i in range(K + 2):
        for j in range(K + 2):
            for k in range(K + 2):
                tmp[i][j] = (tmp[i][j] + p[i][k] * p[k][j]) % 998244353
    p = tmp

# S[N]を出力
print(r[K + 1])