# https://tech.aru-zakki.com/python-pow-matrix/
def matmul(A, B):
    N = len(A)
    K = len(A[0])
    M = len(B[0])

    c = [[0 for _ in range(M)] for _ in range(N)]
    for i in range(N) :
        for j in range(K) :
            for k in range(M) :
                c[i][k] += A[i][j] * B[j][k] % MOD
                c[i][k] %= MOD
    return c

def pow_matrix(A, p):
    n = len(A)
    # 単位行列
    c = [[1 if i == j else 0 for i in range(n)] for j in range(n)]
    while p > 0 :
        if p%2 == 1 :
            c = matmul(c, A)
        A = matmul(A, A)
        p //= 2
    return c

def nPr(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    return g1[n] * g2[n-r] % mod

def nCr(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return (g1[n] * g2[r] % mod) * g2[n-r] % mod

import sys
input = sys.stdin.readline
MOD = 998244353
N, K = map(int, input().split())

g1 = [1, 1] # 元テーブル
g2 = [1, 1] #逆元テーブル
inverse = [0, 1] #逆元テーブル計算用テーブル
fact = [1, 1]

for i in range( 2, K + 1 ):
    g1.append( ( g1[-1] * i ) % MOD )
    inverse.append( ( -inverse[MOD % i] * (MOD//i) ) % MOD )
    g2.append( (g2[-1] * inverse[-1]) % MOD )
    fact.append( (fact[-1] * i) % MOD )

A = [[1 for _ in range(K+2)]]
C = [[0 for _ in range(K+2)] for _ in range(K+2)]
for i in range(K+1):
    for j in range(K+1):
        C[i][j] = nCr(K-j, K-i-j, MOD)
C[0][-1] = 1
C[-1][-1] = 1

CC = pow_matrix(C, N-1)
ans = matmul(A, CC)
print(ans[0][-1])