MOD = 998244353
MAX_V = 2000001

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

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

def COM(n, r):
    if n < r or n < 0 or r < 0:
        return 0
    return fac[n] * finv[r] % MOD * finv[n - r] % MOD

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

def main():
    COMinit()
    N, M = map(int, input().split())

    if N == 1:
        print((M-1)*modinv(2) % MOD)
    else:
        cumnoc = [0] * (M + 1)
        for i in range(M + 1):
            if i * N > M:
                break
            cumnoc[i] = COM(M - i * N + N, N)
    
        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 * modinv(total) % MOD
        print(ans)

if __name__ == "__main__":
    main()