#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;

constexpr int mod = 998244353;

long long fac[200005], finv[200005], inv[200005];

void COMinit() {
    fac[0] = fac[1] = finv[0] = finv[1] = inv[1] = 1;
    for (int i = 2; i < 200005; i++) {
        fac[i] = fac[i - 1] * i % mod;
        inv[i] = mod - inv[mod % i] * (mod / i) % mod;
        finv[i] = finv[i - 1] * inv[i] % mod;
    }
}

long long COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod;
}

long long choose(int n,int k) {
    if(n < 0 || k < 0) return 0;
    if(n == 0) return 1;
    return COM(n+k-1,k-1);
}

int main() {
    COMinit();
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N,M;
    cin >> N >> M;
    vector<int>A(N),B(N);
    for(int i = 0; i < N; i++) {
        cin >> A[i];
    }
    for(int i = 0; i < N; i++) {
        cin >> B[i];
    }
    vector<vector<int>>dp(M,vector<int>(601,1));
    for(int i = 0; i < N; i++) {
        vector<int>a(A[i]+1),b(B[i]+1);
        for(int j = 0; j <= A[i]; j++) {
            a[j] = COM(A[i],j);
        }
        for(int j = 0; j <= B[i]; j++) {
            b[j] = COM(B[i],j);
        }
        reverse(b.begin(),b.end());
        vector<int>c = convolution(a,b);
        vector<int>d(601);
        for(int j = 0; j <= A[i]+B[i]; j++) {
            d[300+j-B[i]] = c[j];
        }
        for(int j = 0; j <= 600; j++) {
            dp[i%M][j] = 1ll*dp[i%M][j]*d[j]%mod;
        }
    }
    vector<int>id(M);
    iota(id.begin(),id.end(),0);
    while(id.size() > 1) {
        vector<int>nxt;
        for(int i = 0; i+1 < id.size(); i += 2) {
            dp[id[i]] = convolution(dp[id[i]],dp[id[i+1]]);
            if(dp[id[i]].size() > 300*M+1) {
                dp[id[i]].resize(300*M+1);
            }
            nxt.push_back(id[i]);
        }
        if(id.size()%2) {
            nxt.push_back(id.back());
        }
        id = nxt;
    }
    cout << dp[id[0]][300*M] << endl;
}