mod = 998244353
N, M = map(int,input().split())
fact = [1]*(N+1)
factinv = [1]*(N+1)

for i in range(2, N+1):
	fact[i] = fact[i-1] * i % mod

factinv[-1] = pow(fact[-1], mod-2, mod)
for i in range(N-1, 1, -1):
	factinv[i] = factinv[i+1] * (i+1) % mod

def cmb(a, b):
	if (a < b) or (b < 0):
		return 0
	return fact[a] * factinv[b] % mod * factinv[a-b] % mod

inv2 = pow(2, mod-2, mod)

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

for i in range(N+1):
	for j in range(N+1):
		# パス
		if i+1 <= N:
			dp[i+1][j] = (dp[i+1][j] + dp[i][j]) % mod
		for k in range(2, min(N-i, N-j+1)+1):
			dp[i+k][j+k-1] = (dp[i+k][j+k-1] + cmb(N-i-1, k-1) * dp[i][j] % mod * fact[k] % mod * inv2) % mod
		# 閉路
		for k in range(5, min(N-i, N-j)+1):
			dp[i+k][j+k] = (dp[i+k][j+k] + cmb(N-i-1, k-1) * dp[i][j] % mod * fact[k-1] % mod * inv2) % mod

if M < N*(N-1)//2 - N:
	print(0)
else:
	print(sum(dp[N][N*(N-1)//2-M:]) % mod)