#include <stdio.h>

long long mod_num = 998244353LL;
long long org_root = 3LL;
int org_length = 998244352;
long long root[10] = {};
int length[10] = {};
long long inverse_root[10] = {};
long long inverse_l[10] = {};

int log_l[10] = {};
long long pow_root[10][16] = {};
long long pow_root_inv[10][16] = {};

long long power_mod (long long a, long long b, long long p) {
  long long ans = 0LL;
  
  a %= p;
  
  if (b <= 0LL) {
    return 1LL;
  }
  
  ans = power_mod(a, b/2LL, p);
  ans = (ans * ans) % p;
  if (b%2LL == 1LL) {
    ans = (ans * a) % p;
  }
  
  return ans;
}

void setup_ntt (int l, int id) {
  int tmp_length = 4;
  log_l[id] = 1;
  
  while(tmp_length < 2*l) {
    tmp_length *= 4;
    log_l[id]++;
  }
  
  root[id] = power_mod(org_root, org_length / tmp_length, mod_num);
  inverse_root[id] = power_mod(root[id], mod_num-2LL, mod_num);
  inverse_l[id] = power_mod((long long) tmp_length, mod_num-2LL, mod_num);
  length[id] = tmp_length;
  
  pow_root[id][log_l[id]-1] = root[id];
  for (int i = log_l[id]-1; i > 0; i--) {
    pow_root[id][i-1] = pow_root[id][i];
    pow_root[id][i-1] *= pow_root[id][i];
    pow_root[id][i-1] %= mod_num;
    pow_root[id][i-1] *= pow_root[id][i-1];
    pow_root[id][i-1] %= mod_num;
  }
  
  pow_root_inv[id][log_l[id]-1] = inverse_root[id];
  for (int i = log_l[id]-1; i > 0; i--) {
    pow_root_inv[id][i-1] = pow_root_inv[id][i];
    pow_root_inv[id][i-1] *= pow_root_inv[id][i];
    pow_root_inv[id][i-1] %= mod_num;
    pow_root_inv[id][i-1] *= pow_root_inv[id][i-1];
    pow_root_inv[id][i-1] %= mod_num;
  }
  
  return;
}

void ntt_4n (long long *a, long long *pow_root, int length, int log_l) {
  long long root_1_4 = pow_root[0];
  
  for (int i = 0; i < length; i++) {
    int idx = 0;
    int tmp = i;
    for (int j = 0; j < log_l; j++) {
      idx <<= 2;
      idx |= (tmp&3);
      tmp >>= 2;
    }
    if (i < idx) {
      long long swap = a[i];
      a[i] = a[idx];
      a[idx] = swap;
    }
  }
  
  for (int i = 0; i < log_l; i++) {
    int step = (1<<(2*i));
    int stepx4 = (step<<2);
    int cnt = length/stepx4;
    long long tmp_root = 1LL;
    for (int j = 0; j < step; j++) {
      long long w1 = tmp_root;
      long long w2 = (w1*w1)%mod_num;
      long long w3 = (w2*w1)%mod_num;
      for (int k = 0; k < cnt; k++) {
        int idx1 = ((k*stepx4)|j);
        int idx2 = (idx1|step);
        int idx3 = (idx1|(2*step));
        int idx4 = (idx2|idx3);
        long long a1 = a[idx1];
        long long a2 = (a[idx2]*w1)%mod_num;
        long long a3 = (a[idx3]*w2)%mod_num;
        long long a4 = (a[idx4]*w3)%mod_num;
        long long wa2 = (a2*root_1_4)%mod_num;
        long long wa4 = (a4*root_1_4)%mod_num;
        long long pad = (mod_num<<1LL);
        a[idx1] = (a1+a2+a3+a4) % mod_num;
        a[idx2] = (a1+wa2-a3-wa4+pad) % mod_num;
        a[idx3] = (a1-a2+a3-a4+pad) % mod_num;
        a[idx4] = (a1-wa2-a3+wa4+pad) % mod_num;
      }
      tmp_root = (tmp_root*pow_root[i])%mod_num;
    }
  }
  
  return;
}

int main () {
  int n = 0;
  int m = 0;
  int a[200000] = {};
  int b[200000] = {};
  
  int res = 0;
  
  long long ans[4000000] = {};
  long long mod_num = 998244353LL;
  
  long long comb[301][301] = {};
  long long cnt[301][301][301] = {};
  
  long long prod[300][601] = {};
  
  long long st[10][1048576] = {};
  int stnum[10] = {};
  int idx = 0;
  
  int logm = 0;
  
  res = scanf("%d", &n);
  res = scanf("%d", &m);
  for (int i = 0; i < n; i++) {
    res = scanf("%d", a+i);
  }
  for (int i = 0; i < n; i++) {
    res = scanf("%d", b+i);
  }
  
  for (int i = 0; i <= 300; i++) {
    comb[i][0] = 1LL;
    comb[i][i] = 1LL;
    for (int j = 1; j < i; j++) {
      comb[i][j] = (comb[i-1][j-1]+comb[i-1][j])%mod_num;
    }
  }
  
  for (int i = 1; i <= 300; i++) {
    for (int j = 0; j <= 300; j++) {
      cnt[i][0][j] = comb[i][j];
    }
    for (int j = 1; j <= 300; j++) {
      for (int k = 0; k < 300; k++) {
        cnt[i][j][k] = (cnt[i][j-1][k]+cnt[i][j-1][k+1])%mod_num;
      }
      if (i >= 300) {
        cnt[i][j][300] = 1LL;
      }
    }
  }
  
  for (int i = 0; i < m; i++) {
    for (int j = 0; j <= 600; j++) {
      prod[i][j] = 1LL;
    }
  }
  
  for (int i = 0; i < n; i++) {
    for (int j = 0; j <= 300; j++) {
      prod[i%m][j+300] *= cnt[a[i]][b[i]][j];
      prod[i%m][j+300] %= mod_num;
    }
    for (int j = 1; j <= 300; j++) {
      prod[i%m][300-j] *= cnt[b[i]][a[i]][j];
      prod[i%m][300-j] %= mod_num;
    }
  }
  
  while ((1<<logm) < m) {
    setup_ntt(600*(1<<logm)+1, logm);
    logm++;
  }
  setup_ntt(600*m+1, logm);
  
  for (int i = 0; i < m; i++) {
    stnum[idx] = 0;
    for (int j = 0; j <= 600; j++) {
      st[idx][j] = prod[i][j];
    }
    while (idx > 0 && stnum[idx-1] == stnum[idx]) {
      ntt_4n(st[idx-1], pow_root[stnum[idx]], length[stnum[idx]], log_l[stnum[idx]]);
      ntt_4n(st[idx], pow_root[stnum[idx]], length[stnum[idx]], log_l[stnum[idx]]);
      for (int j = 0; j < length[stnum[idx]]; j++) {
        st[idx-1][j] *= st[idx][j];
        st[idx-1][j] %= mod_num;
        st[idx][j] = 0LL;
      }
      ntt_4n(st[idx-1], pow_root_inv[stnum[idx]], length[stnum[idx]], log_l[stnum[idx]]);
      for (int j = 0; j <= length[stnum[idx]]; j++) {
        st[idx-1][j] *= inverse_l[stnum[idx]];
        st[idx-1][j] %= mod_num;
      }
      stnum[idx-1]++;
      idx--;
    }
    idx++;
  }
  
  ans[0] = 1LL;
  for (int i = 0; i < idx; i++) {
    ntt_4n(ans, pow_root[logm], length[logm], log_l[logm]);
    ntt_4n(st[i], pow_root[logm], length[logm], log_l[logm]);
    for (int j = 0; j < length[logm]; j++) {
      ans[j] *= st[i][j];
      ans[j] %= mod_num;
    }
    ntt_4n(ans, pow_root_inv[logm], length[logm], log_l[logm]);
    for (int j = 0; j <= 600*m; j++) {
      ans[j] *= inverse_l[logm];
      ans[j] %= mod_num;
    }
    for (int j = 600*m+1; j < length[logm]; j++) {
      ans[j] = 0LL;
    }
  }
  
  printf("%lld\n", ans[300*m]);
  return 0;
}