MOD = 998244353
MAX_V = 2000001

# 階乗、逆元、逆階乗のテーブル
fac = Array.new(MAX_V, 0)
finv = Array.new(MAX_V, 0)
inv = Array.new(MAX_V, 0)

fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1

(2...MAX_V).each do |i|
  fac[i] = fac[i - 1] * i % MOD
  inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD
  finv[i] = finv[i - 1] * inv[i] % MOD
end

n, m = gets.split.map(&:to_i)

cumnoc = Array.new(m + 1, 0)
(0..m).each do |i|
  break if i * n > m
  cumnoc[i] = fac[m - i * n + n] * finv[n] % MOD * finv[m - i * n] % MOD
end

if n == 1
  (0..m).each do |i|
    cumnoc[i] = (cumnoc[i] - n) % MOD
  end
else
  cumnoc[0] = (cumnoc[0] - n) % MOD
end

noc = Array.new(m, 0)
(0...m).each do |i|
  noc[i] = (cumnoc[i] - cumnoc[i + 1]) % MOD
end

ans = 0
(0...m).each do |i|
  ans = (ans + i * noc[i]) % MOD
end

total = cumnoc[0]
ans = ans * total.pow(MOD - 2, MOD) % MOD
puts ans