N,K = map(int, input().split())
mod = 998244353
def matrix_multiply(A, B):
    """2つの行列AとBの乗算を行う"""
    result = [[0 for _ in range(len(B[0]))] for _ in range(len(A))]
    for i in range(len(A)):
        for j in range(len(B[0])):
            for k in range(len(B)):
                result[i][j] = (result[i][j] + (A[i][k] * B[k][j]))%mod
    return result

divsix = pow(6,mod-2,mod)

transition_matrix = [[divsix for _ in range(6)] for _ in range(6)]
ANS = [[divsix for _ in range(6)] for _ in range(6)]

while N:
    if N & 1:
        ANS = matrix_multiply(ANS, transition_matrix)
    transition_matrix = matrix_multiply(transition_matrix, transition_matrix)
    N //= 2
print(ANS[0][K])