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

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+1

ans = 1
sc = defaultdict(int)
sc[0] = 1
for si in range(m):
    dp = defaultdict(lambda: -1)
    for i in range(si, n, m):
        a, b = aa[i], bb[i]
        i = -a
        ndp = defaultdict(int)
        for c in cc[a+b]:
            if dp[i] == -1:
                ndp[i] = c
            else:
                ndp[i] = dp[i]*c%md
            i += 1
        dp = ndp
        # pDB(i, a, b, dp)

    nsc = defaultdict(int)
    for d, v in dp.items():
        for s, c in sc.items():
            if -lim <= s+d <= lim:
                nsc[s+d] += v*c%md
                nsc[s+d] %= md
    sc = nsc

print(sc[0])