def dice_remainder_probability(N, K):
    dp = [[0 for _ in range(6*N+1)] for _ in range(2)]
    dp[0][0] = 1
    for i in range(N):
        dp[(i+1)%2] = [0 for _ in range(6*N+1)]
        for j in range(6*i+1):
            for k in range(1, 7):
                dp[(i+1)%2][j+k] += dp[i%2][j]

    total = 0
    for i in range(K, 6*N+1, 6):
        total += dp[N%2][i]

    return total, 6**N  


def mod_inverse(a, m):
    g, x, y = extended_gcd(a, m)
    if g != 1:
        raise Exception('M')
    else:
        return x % m

def extended_gcd(a, b):
    if a == 0:
        return b, 0, 1
    else:
        g, x, y = extended_gcd(b % a, a)
        return g, y - (b // a) * x, x

N, K = map(int, input().split())
P, Q = dice_remainder_probability(N, K)
R = (P * mod_inverse(Q, 998244353)) % 998244353

print(R)