import numpy as np

MOD = 998244353
MAX_V = 2000001
FACTMXINV = 51625059

fac = [0 for _ in range(MAX_V)]
finv = [0 for _ in range(MAX_V)]

def COMint():
    fac[0] = fac[1] = 1
    finv[0] = 1
    for i in range(2, MAX_V):
        fac[i] = (fac[i - 1] * i) % MOD
    finv[MAX_V-1] = FACTMXINV
    for i in range(MAX_V-2, 0, -1):
        finv[i] = (finv[i + 1] * (i + 1)) % MOD

def COM(n, r):
    return fac[n] * finv[r] % MOD * finv[n - r] % MOD

def modinv(x):
    return pow(x, MOD - 2, MOD)

def main():
    COMint()
    N, M = map(int, input().split())
    
    if N == 1:
        print((M - 1)*finv[2] % MOD)
    else:
        cnt = [0 for _ in range(M//N + 2)]
        for k in range(0, M//N + 1):
            cnt[k] = COM(M - k*N + N, N)
        cnt[0] = (cnt[0] - N) % MOD
        ans = 0
        for k in range(0, M//N + 1):
            ans = (ans + k*(cnt[k] - cnt[k + 1])) % MOD
        ans = (ans * modinv(cnt[0])) % MOD
        print(ans)
        
if __name__ == "__main__":
    main()