mod = 998244353


def fft_inplace(a, w):
    n = len(a)
    m = n
    t = 1
    while m >= 2:
        mh = m >> 1
        for i in range(0, n, m):
            for s in range(mh):
                j, k = i+s, i+mh+s
                a[j], u = a[j]+a[k], a[j]-a[k]
                a[k] = u * w[s*t] % mod
        m = mh
        t *= 2


def ifft_inplace(a, w):
    n = len(a)
    m = 2
    t = -(n >> 1)
    while m <= n:
        mh = m >> 1
        for i in range(0, n, m):
            for s in range(mh):
                j, k = i+s, i+mh+s
                u = a[k] * w[s*t] % mod
                a[j], a[k] = a[j]+u, a[j]-u
        m <<= 1
        t //= 2
    n_inv = pow(n, mod-2, mod)
    for i in range(n):
        a[i] = a[i] * n_inv % mod


n, m = map(int, input().split())
fixed_n = 1 << ((n+1)*2).bit_length()

w_root = pow(3, (mod-1)//fixed_n, mod)
w = [1] * fixed_n
for i in range(1, fixed_n):
    w[i] = w[i-1] * w_root % mod

frac = [1] * (n + 1)
for i in range(1, n+1):
    frac[i] = frac[i-1] * i % mod
frac_inv = [0] * (n+1)
frac_inv[n] = pow(frac[n], mod-2, mod)
for i in range(1, n+1)[::-1]:
    frac_inv[i-1] = frac_inv[i] * i % mod

dp1 = [0] * fixed_n
dp1[0] = 1

t = [0] * fixed_n
for i in range(n+1):
    t[i] = (pow(2, i, mod)-1) * pow(pow(2, i, mod) * frac[i], mod-2, mod) % mod

fft_inplace(t, w)

ans_sub = [0] * (n+1)
for k in range(min(n, m+1)):
    fft_inplace(dp1, w)
    for i, j in enumerate(t):
        dp1[i] = dp1[i] * j % mod
    ifft_inplace(dp1, w)

    pow_tmp = 1
    for i in range(k+1, n+1)[::-1]:
        ans_sub[i] += dp1[i] * pow_tmp % mod
        pow_tmp = pow_tmp * (m - k) % mod
    for i in range(n+1, fixed_n):
        dp1[i] = 0

ans = sum(ans_sub[i] % mod * frac_inv[n-i] for i in range(n+1)) % mod
ans = ans * pow(2, n, mod) * frac[n] % mod
print(ans)