#include <array>
#include <cstdio>
#include <cmath>
#include <cassert>
#include <vector>
#include <iostream>
using namespace std;

template<int mod>
class modint {
    int val = 0;
    constexpr static int normalize(long long x) {
        if (0 <= x and x < mod) return static_cast<int>(x);
        else { x %= mod; return static_cast<int>(x >= 0 ? x : x + mod); }
    }
public:
    static const int modulus = mod;
    modint() {}
    constexpr modint(long long n) : val(normalize(n)) {}
    constexpr int value() const { return val; }
    constexpr modint operator-() const { return modint(mod - val); }
    constexpr modint inverse() const {
        long long x = mod, y = val, p = 1, q = 0, r = 0, s = 1;
        while (y != 0) {
            long long u = x / y;
            long long x0 = y; y = x - y * u; x = x0;
            long long r0 = p - r * u, s0 = q - s * u;
            p = r; r = r0; q = s; s = s0;
        }
        return modint(q);
    }
    constexpr const modint pow(long long e) const {
        if (e < 0) return pow(-e).inverse();
        long long ans = 1, p = val;
        while (e > 0) {
            if (e % 2 != 0) ans = (ans * p) % mod;
            p = (p * p) % mod;
            e >>= 1;
        }
        return modint(ans);
    }
    constexpr modint &operator+=(const modint r) {
        val += r.value();
        if (val >= mod) val -= mod;
        return *this;
    }
    constexpr modint &operator-=(const modint r) {
        val -= r.value();
        if (val < 0) val += mod;
        return *this;
    }
    constexpr modint &operator*=(const modint r) {
        val = (long long)val * r.value() % mod;
        return *this;
    }
    constexpr modint &operator/=(const modint r) {
        if (r.value() == 2) {
            val = (val % 2 ? val + mod : val) / 2;
        } else {
            val = (long long)val * r.inverse().value() % mod;
        }
        return *this;
    }

    friend constexpr modint operator+(const modint l, const modint r) {
        const int newval = l.value() + r.value();
        return newval >= mod ? newval - mod : newval;
    }
    friend constexpr modint operator-(const modint l, const modint r) { return l + (- r); }
    friend constexpr modint operator*(const modint l, const modint r) { return (long long)l.value() * r.value(); }
    friend constexpr modint operator/(const modint l, const modint r) { return l * r.inverse(); }
    friend constexpr bool operator==(const modint l, const modint r) { return l.value() == r.value(); }
    friend constexpr bool operator!=(const modint l, const modint r) { return l.value() != r.value(); }
};

constexpr int M = 998244353;
using mint = modint<M>;

namespace NTT {
template<typename T>
constexpr bool is_primitive_root(int i) {
    constexpr int p = T::modulus;
    int d = 2, r = p - 1;
    while ((long long)d * d <= r) {
        if (r % d == 0) {
            if (T(i).pow((p - 1) / d).value() == 1) return false;
            do { r /= d; } while (r % d == 0);
        }
        d++;
    }
    if (r > 1 and T(i).pow((p - 1) / r).value() == 1) return false;
    return true;
}

template<typename T>
constexpr T primitive_root() {
    constexpr int p = T::modulus;
    for (int i = 2; i < p; i++) if (is_primitive_root<T>(i)) return i;
    return 0;
}

template<typename T>
void ntt(vector<T> &a, bool inv) {
    constexpr int p = T::modulus;
    constexpr T r = primitive_root<T>();
    const int n = int(a.size());
    assert((p - 1) % n == 0);
    const int expn = (p - 1) / n * (inv ? -1 : 1);
    const T zn = r.pow(expn);
    auto b = a;
    for (int step = n / 2; step > 0; step /= 2) {
        const T wn = zn.pow(step);
        T w = 1;
        for (int t = 0, tmax = n / step / 2; t < tmax; t++) {
            for (int offset = 0; offset < step; offset++) {
                const int i = offset + step * t, j = i + step * t;
                assert(j + step < n);
                const T x = a[j], y = w * a[j + step];
                b[i] = x + y;
                b[i + n/2] = x - y;
            }
            w *= wn;
        }
        if (inv) for (int i = 0; i < n; i++) b[i] /= 2;
        swap(a, b);
    }
}
};

int main() {
    int n, m; scanf("%d %d", &n, &m);
    vector<int> a(n), b(n);
    for (int i = 0; i < n; i++) scanf(" %d", &a[i]);
    for (int i = 0; i < n; i++) scanf(" %d", &b[i]);

    vector<mint> q1(1 << 17, 1), q2(1 << 17, 1);
    array<array<mint, 601>, 601> comb;
    for (int i = 0; i < 601; ++i)
        for (int j = 0; j < 601; ++j)
            if (j == 0) comb[i][j] = 1;
            else if (i == 0) comb[i][j] = 0;
            else comb[i][j] = comb[i-1][j] + comb[i-1][j-1];
    array<array<vector<mint>, 301>, 301> memo;
    for (int i = 0; i < m; ++i) {
        vector<mint> tmp(1 << 17, 0);
        if (memo[a[i]][b[i]].empty()) {
            for (int x = 300 - b[i]; x <= 300 + a[i]; ++x)  {
                mint t = 1;
                for (int j = i; j < n; j += m)
                    t *= comb[a[j] + b[j]][x - 300 + b[j]];
                tmp[x] = t;
            }
            memo[a[i]][b[i]] = tmp;
        } else
            tmp = memo[a[i]][b[i]];
        NTT::ntt(tmp, false);
        for (int j = 0; j < 1 << 17; ++j)
            (i < m / 2 ? q1 : q2)[j] *= tmp[j];
    }

    NTT::ntt(q1, true);
    NTT::ntt(q2, true);
    const int offset = 300 * m;
    mint ans = 0;
    for (int i = 0; i <= offset; ++i)
        ans += q1[i] * q2[offset - i];
    cout << ans.value() << '\n';
}