import sys
input = sys.stdin.readline

mod=998244353

INV5=pow(5,mod-2,mod)

N,K=list(map(int,input().split()))

# 行列の計算（numpyを使えないとき,modを使用）
def prod(A,B,k,l,m):# A:k*l,B:l*m
    C=[[None for i in range(m)] for j in range(k)]

    for i in range(k):
        for j in range(m):
            ANS=0
            for pl in range(l):
                ANS=(ANS+A[i][pl]*B[pl][j])%mod

            C[i][j]=ANS

    return C

def plus(A,B,k,l):# a,B:k*l
    C=[[None for i in range(l)] for j in range(k)]

    for i in range(k):
        for j in range(l):
            C[i][j]=(A[i][j]+B[i][j])%mod

A=[[0]*(N*4+1) for i in range(N*4+1)]

for i in range(N*4):
    if i%4==0:
        A[i][0]+=4*INV5
    else:
        A[i][0]+=3*INV5

for i in range(1,N*4):
    if i%4!=0:
        A[i][1]+=INV5

for i in range(1,N*4+1):
    A[i-1][i]+=INV5

A[0][0]=INV5*4

POWA=[A]

for i in range(60):
    POWA.append(prod(POWA[-1],POWA[-1],N*4+1,N*4+1,N*4+1)) # ベキを求めて

X=[0]*(N*4+1)
X[0]=1
X=[X]

n=K
while n:
    X=prod(X,POWA[n.bit_length()-1],1,N*4+1,N*4+1) # n乗の場合
    n-=1<<(n.bit_length()-1)

#print(X)
print(X[0][-1]%mod)