#include <stdio.h>

int main () {
  int n = 0;
  int m = 0;
  int a[200000] = {};
  int b[200000] = {};
  
  int res = 0;
  
  long long dp[2][900001] = {};
  long long mod_num = 998244353LL;
  
  long long comb[301][301] = {};
  long long cnt[301][301][301] = {};
  
  long long prod[300][601] = {};
  
  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;
    }
  }
  
  dp[0][45000] = 1LL;
  for (int i = 0; i < m; i++) {
    int b = i+1;
    if (b > m-i-1) {
      b = m-i-1;
    }
    for (int j = -300*b; j <= 300*b; j++) {
      dp[(i+1)%2][j+45000] = 0LL;
    }
    for (int j = -300*b; j <= 300*b; j++) {
      for (int k = -300; k <= 300; k++) {
        dp[(i+1)%2][j+45000] += dp[i%2][j+45000+k]*prod[i][k+300];
        dp[(i+1)%2][j+45000] %= mod_num;
      }
    }
  }
  
  printf("%lld\n", dp[m%2][45000]);
  return 0;
}