#include <iostream>
#include <deque>
#include <vector>

#include <atcoder/modint>
#include <atcoder/convolution>

using mint = atcoder::modint998244353;

constexpr int L = 300;
constexpr int M = 2 * L + 1;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int n, m;
    std::cin >> n >> m;

    std::vector<int> a(n), b(n);
    for (auto &&e : a) std::cin >> e;
    for (auto &&e : b) std::cin >> e;


    std::vector binom(M, std::vector<mint>(M));
    for (int i = 0; i < M; ++i) {
        binom[i][0] = binom[i][i] = 1;
        for (int j = 1; j < i; ++j) {
            binom[i][j] = binom[i - 1][j - 1] + binom[i - 1][j];
        }
    }

    std::deque<std::vector<mint>> fs;
    for (int i = 0; i < m; ++i) {
        int miny = L;
        std::vector<int> x, y;
        for (int j = i; j < n; j += m) {
            x.push_back(a[j]);
            y.push_back(b[j]);
            miny = std::min(miny, b[j]);
        }
        const int siz = x.size();
        std::vector<mint> f(M, 0);
        std::fill(f.begin() + (L - miny), f.end(), 1);
        for (int j = 0; j < siz; ++j) {
            for (int d = -miny; d <= L; ++d) {
                f[L + d] *= binom[x[j] + y[j]][d + y[j]];
            }
        }
        fs.emplace_back(std::move(f));
    }

    while (fs.size() >= 2) {
        auto f = fs.front();
        fs.pop_front();
        auto g = fs.front();
        fs.pop_front();
        fs.push_back(atcoder::convolution(f, g));
    }

    std::cout << fs.front()[m * L].val() << std::endl;
}