// from 0:15
#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rep1(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < (t); ++i)
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define pob pop_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define snuke srand((unsigned)clock()+(unsigned)time(NULL));
#define newline puts("")
using namespace std;
template<typename T> using vc = vector<T>;
template<typename T> using vv = vc<vc<T>>;
template<typename T> using PQ = priority_queue<T,vc<T>,greater<T>>;
using uint = unsigned; using ull = unsigned long long;
using vi = vc<int>; using vvi = vv<int>; using vvvi = vv<vi>;
using ll = long long; using vl = vc<ll>; using vvl = vv<ll>; using vvvl = vv<vl>;
using P = pair<int,int>; using vp = vc<P>; using vvp = vv<P>;
int geti(){int x;scanf("%d",&x);return x;}
vi pm(int n, int s=0) { vi a(n); iota(rng(a),s); return a;}
template<typename T>istream& operator>>(istream&i,vc<T>&v){rep(j,sz(v))i>>v[j];return i;}
template<typename T>string join(const T&v,const string& d=""){stringstream s;rep(i,sz(v))(i?s<<d:s)<<v[i];return s.str();}
template<typename T>ostream& operator<<(ostream&o,const vc<T>&v){if(sz(v))o<<join(v," ");return o;}
template<typename T1,typename T2>istream& operator>>(istream&i,pair<T1,T2>&v){return i>>v.fi>>v.se;}
template<typename T1,typename T2>ostream& operator<<(ostream&o,const pair<T1,T2>&v){return o<<v.fi<<","<<v.se;}
template<typename T1,typename T2>void operator--(pair<T1,T2>&a,int){a.fi--;a.se--;}
template<typename T>void operator--(vc<T>&a,int){for(T&x:a)x--;}
template<typename T>void operator++(vc<T>&a,int){for(T&x:a)x++;}
template<typename T>void operator+=(vc<T>&a,T b){for(T&x:a)x+=b;}
template<typename T>void operator+=(vc<T>&a,const vc<T>&b){a.insert(a.end(),rng(b));}
template<typename T1,typename T2>bool mins(T1& x,const T2&y){if(x>y){x=y;return true;}else return false;}
template<typename T1,typename T2>bool maxs(T1& x,const T2&y){if(x<y){x=y;return true;}else return false;}
template<typename Tx, typename Ty>Tx dup(Tx x, Ty y){return (x+y-1)/y;}
template<typename T>ll suma(const vc<T>&a){ll res(0);for(auto&&x:a)res+=x;return res;}
template<typename T>ll suma(const vv<T>&a){ll res(0);for(auto&&x:a)res+=suma(x);return res;}
template<typename T>void uni(T& a){sort(rng(a));a.erase(unique(rng(a)),a.end());}
template<typename T>void prepend(vc<T>&a,const T&x){a.insert(a.begin(),x);}
const double eps = 1e-10;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#define dame { puts("-1"); return;}
#define yes { puts("Yes"); return;}
#define no { puts("No"); return;}
#define ret(x) { cout<<(x)<<endl; return;}
#define yn {puts("Yes");}else{puts("No");}
const int M = 300;
const int M2 = M*2+1;

// Mod int
const uint mod = 998244353;
struct mint {
  uint x;
  mint(): x(0) {}
  mint(ll x):x((x%mod+mod)%mod) {}
  mint operator-() const { return mint(0) - *this;}
  mint operator~() const { return mint(1) / *this;}
  mint& operator+=(const mint& a) { if((x+=a.x)>=mod) x-=mod; return *this;}
  mint& operator-=(const mint& a) { if((x+=mod-a.x)>=mod) x-=mod; return *this;}
  mint& operator*=(const mint& a) { x=(ull)x*a.x%mod; return *this;}
  mint& operator/=(const mint& a) { x=(ull)x*a.pow(mod-2).x%mod; return *this;}
  mint operator+(const mint& a) const { return mint(*this) += a;}
  mint operator-(const mint& a) const { return mint(*this) -= a;}
  mint operator*(const mint& a) const { return mint(*this) *= a;}
  mint operator/(const mint& a) const { return mint(*this) /= a;}
  mint pow(ll t) const {
    mint res = 1; for (mint p=x;t;p*=p,t>>=1) if (t&1) res *= p; return res;
  }
  mint ppow(ll t) const { int p=mod-1; return pow((t%p+p)%p);}
  bool operator<(const mint& a) const { return x < a.x;}
  bool operator==(const mint& a) const { return x == a.x;}
  bool operator!=(const mint& a) const { return x != a.x;}
};
mint ex(mint x, ll t) { return x.pow(t);}
istream& operator>>(istream&i,mint&a) {i>>a.x;return i;}
//*
ostream& operator<<(ostream&o,const mint&a) {o<<a.x;return o;}
/*/
ostream& operator<<(ostream&o, const mint&x) {
  int a = x.x, b = 1;
  rep(s,2)rep1(i,1000) {
    int y = ((s?-x:x)*i).x; if (abs(a)+b > y+i) a = s?-y:y, b = i;
  }
  o<<a; if (b != 1) o<<'/'<<b; return o;
}//*/
using vm = vector<mint>;
using vvm = vector<vm>;
struct modinv {
  int n; vm d;
  modinv(): n(2), d({0,1}) {}
  mint operator()(int i) { while (n <= i) d.pb(-d[mod%n]*(mod/n)), ++n; return d[i];}
  mint operator[](int i) const { return d[i];}
} invs;
struct modfact {
  int n; vm d;
  modfact(): n(2), d({1,1}) {}
  mint operator()(int i) { while (n <= i) d.pb(d.back()*n), ++n; return d[i];}
  mint operator[](int i) const { return d[i];}
} facs;
struct modfactinv {
  int n; vm d;
  modfactinv(): n(2), d({1,1}) {}
  mint operator()(int i) { while (n <= i) d.pb(d.back()*invs(n)), ++n; return d[i];}
  mint operator[](int i) const { return d[i];}
} ifacs;
mint comb(int a, int b) {
  if (a < b || b < 0) return 0;
  return facs(a)*ifacs(b)*ifacs(a-b);
}
//

struct NTT {
  int ceil_pow2(int n) { int x = 0; while ((1U<<x) < (uint)(n)) x++; return x;}
  int bsf(uint n) { return __builtin_ctz(n);}
  const static int _g = 3; // primitive root !!!
  void butterfly(vm& a) {
    static mint g = _g; int n = sz(a), h = ceil_pow2(n);
    static bool first = true; static mint sum_e[30];
    if (first) {
      first = false; mint es[30], ies[30]; int cnt2 = bsf(mod - 1);
      mint e = g.pow((mod - 1) >> cnt2), ie = ~e;
      for (int i = cnt2; i >= 2; i--) {
        es[i - 2] = e; ies[i - 2] = ie; e *= e; ie *= ie;
      }
      mint now = 1;
      rep(i,cnt2-1) sum_e[i] = es[i] * now, now *= ies[i];
    }
    rep1(ph,h) {
      int w = 1<<(ph-1), p = 1<<(h-ph); mint now = 1;
      rep(s,w) {
        int offset = s << (h - ph + 1);
        for (int i = 0; i < p; i++) {
          auto l = a[i + offset], r = a[i + offset + p] * now;
          a[i + offset] = l + r; a[i + offset + p] = l - r;
        }
        now *= sum_e[bsf(~(uint)(s))];
      }
    }
  }
  void butterfly_inv(vm& a) {
    static mint g = _g; int n = sz(a), h = ceil_pow2(n);
    static bool first = true; static mint sum_ie[30];
    if (first) {
      first = false; mint es[30], ies[30];
      int cnt2 = bsf(mod - 1); mint e = g.pow((mod - 1) >> cnt2), ie = ~e;
      for (int i = cnt2; i >= 2; i--) {
        es[i - 2] = e; ies[i - 2] = ie; e *= e; ie *= ie;
      }
      mint now = 1; rep(i,cnt2-1) sum_ie[i] = ies[i] * now, now *= es[i];
    }
    for (int ph = h; ph >= 1; ph--) {
      int w = 1 << (ph - 1), p = 1 << (h - ph); mint inow = 1;
      rep(s,w) {
        int offset = s << (h - ph + 1);
        for (int i = 0; i < p; i++) {
          auto l = a[i + offset], r = a[i + offset + p];
          a[i + offset] = l + r;
          a[i + offset + p] = (ull)(mod + l.x - r.x) * inow.x;
        }
        inow *= sum_ie[bsf(~(uint)(s))];
      }
    }
  }
  vm operator()(vm a, vm b) {
    int n = sz(a), m = sz(b); if (!n || !m) return {};
    if (min(n, m) <= 60) {
      if (n < m) swap(n, m), swap(a, b);
      vm ans(n+m-1); rep(i,n)rep(j,m) ans[i + j] += a[i] * b[j];
      return ans;
    }
    int z = 1 << ceil_pow2(n+m-1);
    a.resize(z); butterfly(a); b.resize(z); butterfly(b);
    rep(i,z) a[i] *= b[i];
    butterfly_inv(a); a.resize(n + m - 1); mint iz = ~(mint(z));
    rep(i,n+m-1) a[i] *= iz;
    return a;
  }
} ntt;

struct fps : vm {
#define d (*this)
#define s int(vm::size())
  template<class...Args> fps(Args...args): vm(args...) {}
  fps(initializer_list<mint> a): vm(rng(a)) {}
  int size() const { return vm::size();}
  void rsz(int n) { if (s < n) resize(n);}
  fps& low_(int n) { resize(n); return d;}
  fps low(int n) const { return fps(d).low_(n);}
  fps low(fps a, int n) const { return a.low_(n);}
  fps& rev_() { reverse(rng(d)); return d;}
  fps rev() const { return fps(d).rev_();}
  fps rev(fps a) const { return a.rev_();}
  fps odd(int si=1) const { fps r(s/2); for(int i=si;i<s;i+=2) r[i>>1]=d[i]; return r;}
  mint& operator[](int i) { rsz(i+1); return vm::operator[](i);}
  mint operator[](int i) const { return i<s ? vm::operator[](i) : 0;}
  mint operator()(mint x) const { mint r; drep(i,s) r = r*x+d[i]; return r;}
  fps operator<<(int a) const { fps r(d); r.insert(r.begin(), a, 0); return r;}
  fps operator>>(int a) const { fps r(d); r.rsz(a); r.erase(r.begin(), r.begin()+a); return r;}
  fps& fit() { while (s && !back().x) pop_back(); return d;}
  fps operator-() const { fps r(d); rep(i,s) r[i] = -r[i]; return r;}
  fps& operator+=(const fps& a) { rsz(sz(a)); rep(i,sz(a)) d[i] += a[i]; return d;}
  fps& operator-=(const fps& a) { rsz(sz(a)); rep(i,sz(a)) d[i] -= a[i]; return d;}
  fps& operator*=(const fps& a) { return d = ntt(d, a);}
  fps& operator/=(const fps& a) {
    int w = s-sz(a)+1; if (w <= 0) return d = 0;
    return (rev_().low_(w) *= a.rev().inv(w)).low_(w).rev_();
  }
  fps& operator%=(const fps& a) { return (d -= d/a*a).low_(sz(a)-1);}
  fps& operator*=(mint a) { rep(i,s) d[i] *= a; return d;}
  fps& operator/=(mint a) { return d *= ~a;}
  fps& operator*=(int a) { return d *= mint(a);}
  fps& operator/=(int a) { return d /= mint(a);}
  fps operator+(const fps& a) const { return fps(d) += a;}
  fps operator-(const fps& a) const { return fps(d) -= a;}
  fps operator*(const fps& a) const { return fps(d) *= a;}
  fps operator/(const fps& a) const { return fps(d) /= a;}
  fps operator%(const fps& a) const { return fps(d) %= a;}
  fps operator*(mint a) const { return fps(d) *= a;}
  fps operator/(mint a) const { return fps(d) *= ~a;}
  fps operator*(int a) const { return fps(d) *= mint(a);}
  fps operator/(int a) const { return fps(d) /= mint(a);}
  fps& mul1(mint a) { pb(0); drep(i,s-1) d[i+1] += d[i], d[i] *= a; return d;} // *=(x+a), /=(x+a)
  fps& div1(mint a) { mint pre = back(); pop_back(); drep(i,s) std::swap(pre, d[i]), pre -= d[i]*a; return d;}
  fps dif() const { fps r(s-1); rep1(i,sz(r)) r[i-1] = d[i]*i; return r;}
  fps integ() const { fps r(s+1); rep1(i,s) r[i] = d[i-1]*invs(i); return r;}
  fps inv() const { return inv(s);}
  fps inv(int w) const {
    fps r({~d[0]});
    for (int i = 1; i < w; i <<= 1) r = r*2 - low(r*r*low(i<<1), i<<1);
    return r.low_(w);
  }
// [fps_nth]
// [fps_multipointeval]
// [fps_taylorshift]
// [fps_combconv]
#undef s
#undef d
};

struct Solver {
  void solve() {
    int n,m;
    scanf("%d%d",&n,&m);
    vp a(n);
    rep(i,n) cin>>a[i].fi;
    rep(i,n) cin>>a[i].se;

    vvm d(m,vm(M2,1));
    rep(si,m) {
      for (int i = si; i < n; i += m) {
        auto [l,r] = a[i];
        fps x;
        rep(j,l+r+1) x[M+(r-j)] = comb(l+r,j);
        rep(j,M2) d[si][j] *= x[j];
      }
    }
    queue<fps> q;
    rep(i,m) q.emplace(d[i]);
    while (sz(q) > 1) {
      fps a = q.front(); q.pop();
      fps b = q.front(); q.pop();
      q.push(a*b);
    }
    cout<<q.front()[M*m]<<endl;
  }
};

int main() {
  // cin.tie(nullptr); ios::sync_with_stdio(false);
  int ts = 1;
  // scanf("%d",&ts);
  rep1(ti,ts) {
    Solver solver;
    solver.solve();
  }
  return 0;
}