MOD = 998244353
MAX_V = 2000001

# 階乗、逆元、逆階乗のテーブル
fac = [0 for _ in range(MAX_V)]
finv = [0 for _ in range(MAX_V)]
inv = [0 for _ in range(MAX_V)]

fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1
for i in range(2, MAX_V):
    fac[i] = fac[i - 1] * i % MOD
    inv[i] = MOD - inv[MOD % i] * (MOD // i) % MOD
    finv[i] = finv[i - 1] * inv[i] % MOD

N, M = map(int, input().split())

cumnoc = [0] * (M + 1)
for i in range(M + 1):
    if i * N > M:
        break
    cumnoc[i] = fac[M - i * N + N] * finv[N] % MOD * finv[M - i * N] % MOD

if N == 1:
    for i in range(M + 1):
        cumnoc[i] = (cumnoc[i] - N) % MOD
else:
    cumnoc[0] = (cumnoc[0] - N) % MOD

noc = [0] * M
for i in range(M):
    noc[i] = (cumnoc[i] - cumnoc[i + 1]) % MOD

ans = 0
for i in range(M):
    ans = (ans + i * noc[i]) % MOD

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