mod = 998244353
N,M = map(int,input().split())
dp = [[0 for m in range(M + 1)] for n in range(N + 1)]
for n in range(N):
  for m in range(M + 1):
    a = 0
    if m == 0:
      a = 1
    b = (a + dp[n][m]) % mod
    for mm in range(M + 1):
      if m + mm <= M:
        dp[n + 1][m + mm] = (dp[n + 1][m + mm] + a * dp[n][mm] % mod)
      if m + mm + 1 <= M:
        c = dp[n][mm]
        if mm == 0:
          c += 1
        dp[n + 1][m + mm + 1] = (dp[n + 1][m + mm + 1] + b * c % mod) % mod
ans = dp[N][M]
print(ans)