MOD = 998244353i64
n, m = read_line.split.map(&.to_i)
if n <= 10 && (1 << n) - 1 < m
  puts 0
  exit
end
dp = Array.new(n) { Array.new(m + 1, 0i64) }
dp[0][0] = 1
dp[0][1] = 1
1.upto(n - 1) do |i|
  0.upto(m) do |j|
    dp[i][j] += dp[i - 1][j]
    dp[i][j] %= MOD
    if j < m
      dp[i][j + 1] += dp[i - 1][j]
      dp[i][j + 1] %= MOD
    end
    1.upto(m - j - 1) do |k|
      dp[i][j + k + 1] += dp[i - 1][j] * dp[i - 1][k]
      dp[i][j + k + 1] %= MOD
    end
  end
end
puts dp[n - 1][m]