import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
# md = 10**9+7
md = 998244353

IMAG = 911660635
IIMAG = 86583718
rate2 = (
    0, 911660635, 509520358, 369330050, 332049552, 983190778, 123842337, 238493703, 975955924, 603855026, 856644456,
    131300601, 842657263, 730768835, 942482514, 806263778, 151565301, 510815449, 503497456, 743006876, 741047443,
    56250497,
    867605899, 0)
irate2 = (0, 86583718, 372528824, 373294451, 645684063, 112220581, 692852209, 155456985, 797128860, 90816748, 860285882,
          927414960, 354738543, 109331171, 293255632, 535113200, 308540755, 121186627, 608385704, 438932459, 359477183,
          824071951, 103369235, 0)
rate3 = (
    0, 372528824, 337190230, 454590761, 816400692, 578227951, 180142363, 83780245, 6597683, 70046822, 623238099,
    183021267,
    402682409, 631680428, 344509872, 689220186, 365017329, 774342554, 729444058, 102986190, 128751033, 395565204, 0)
irate3 = (0, 509520358, 929031873, 170256584, 839780419, 282974284, 395914482, 444904435, 72135471, 638914820, 66769500,
          771127074, 985925487, 262319669, 262341272, 625870173, 768022760, 859816005, 914661783, 430819711, 272774365,
          530924681, 0)

def butterfly(a):
    n = len(a)
    h = (n-1).bit_length()
    le = 0
    while le < h:
        if h-le == 1:
            p = 1 << (h-le-1)
            rot = 1
            for s in range(1 << le):
                offset = s << (h-le)
                for i in range(p):
                    l = a[i+offset]
                    r = a[i+offset+p]*rot
                    a[i+offset] = (l+r)%md
                    a[i+offset+p] = (l-r)%md
                rot *= rate2[(~s & -~s).bit_length()]
                rot %= md
            le += 1
        else:
            p = 1 << (h-le-2)
            rot = 1
            for s in range(1 << le):
                rot2 = rot*rot%md
                rot3 = rot2*rot%md
                offset = s << (h-le)
                for i in range(p):
                    a0 = a[i+offset]
                    a1 = a[i+offset+p]*rot
                    a2 = a[i+offset+p*2]*rot2
                    a3 = a[i+offset+p*3]*rot3
                    a1na3imag = (a1-a3)%md*IMAG
                    a[i+offset] = (a0+a2+a1+a3)%md
                    a[i+offset+p] = (a0+a2-a1-a3)%md
                    a[i+offset+p*2] = (a0-a2+a1na3imag)%md
                    a[i+offset+p*3] = (a0-a2-a1na3imag)%md
                rot *= rate3[(~s & -~s).bit_length()]
                rot %= md
            le += 2

def butterfly_inv(a):
    n = len(a)
    h = (n-1).bit_length()
    le = h
    while le:
        if le == 1:
            p = 1 << (h-le)
            irot = 1
            for s in range(1 << (le-1)):
                offset = s << (h-le+1)
                for i in range(p):
                    l = a[i+offset]
                    r = a[i+offset+p]
                    a[i+offset] = (l+r)%md
                    a[i+offset+p] = (l-r)*irot%md
                irot *= irate2[(~s & -~s).bit_length()]
                irot %= md
            le -= 1
        else:
            p = 1 << (h-le)
            irot = 1
            for s in range(1 << (le-2)):
                irot2 = irot*irot%md
                irot3 = irot2*irot%md
                offset = s << (h-le+2)
                for i in range(p):
                    a0 = a[i+offset]
                    a1 = a[i+offset+p]
                    a2 = a[i+offset+p*2]
                    a3 = a[i+offset+p*3]
                    a2na3iimag = (a2-a3)*IIMAG%md
                    a[i+offset] = (a0+a1+a2+a3)%md
                    a[i+offset+p] = (a0-a1+a2na3iimag)*irot%md
                    a[i+offset+p*2] = (a0+a1-a2-a3)*irot2%md
                    a[i+offset+p*3] = (a0-a1-a2na3iimag)*irot3%md
                irot *= irate3[(~s & -~s).bit_length()]
                irot %= md
            le -= 2

def multiply(s, t):
    n = len(s)
    m = len(t)
    if min(n, m) <= 60:
        a = [0]*(n+m-1)
        for i in range(n):
            if i%8 == 0:
                for j in range(m):
                    a[i+j] += s[i]*t[j]
                    a[i+j] %= md
            else:
                for j in range(m):
                    a[i+j] += s[i]*t[j]
        return [x%md for x in a]
    a = s.copy()
    b = t.copy()
    z = 1 << (n+m-2).bit_length()
    a += [0]*(z-n)
    b += [0]*(z-m)
    butterfly(a)
    butterfly(b)
    for i in range(z):
        a[i] *= b[i]
        a[i] %= md
    butterfly_inv(a)
    a = a[:n+m-1]
    iz = pow(z, md-2, md)
    return [v*iz%md for v in a]

from collections import defaultdict

cc = []
for i in range(601):
    cc.append([1])
    for j in range(1, i):
        cc[i].append((cc[i-1][j-1]+cc[i-1][j])%md)
    cc[i].append(1)
# p2D(cc)

n, m = LI()
aa = LI()
bb = LI()
lim = 300*150

ans = 1
sc = [1]
mid = 0
for si in range(m):
    dp = [-1]*601
    for j in range(si, n, m):
        a, b = aa[j], bb[j]
        i = -a+300
        ndp = [0]*601
        for c in cc[a+b]:
            if dp[i] == -1:
                ndp[i] = c
            elif dp[i]:
                ndp[i] = dp[i]*c%md
            i += 1
        dp = ndp

    mid += 300
    sc = multiply(sc, dp)[:lim*2+1]
# pDB(sc)

print(sc[mid])