#include <bits/stdc++.h>
using namespace std;
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cout << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cout.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
const long long MAX = 2005;
long long mod = 1e9 + 7;
long long add(long long x, long long y) {
  x += y;
  if (x > mod) x -= mod;
  return x;
}
long long sub(long long x, long long y) {
  x -= y;
  if (x < 0) x += mod;
  return x;
}
long long mul(long long x, long long y) { return (x * y) % mod; }
long long power(long long a, long long x) {
  long long rt = 1;
  while (x > 0) {
    if (x & 1) rt = mul(rt, a);
    x >>= 1;
    a = mul(a, a);
  }
  return rt;
}
long long ncr[MAX][MAX];
long long fact[MAX];
long long facti[MAX];
void pre() {
  long long i, j;
  for (i = 0; i < MAX; i++) {
    if (i == 0)
      fact[i] = 1;
    else
      fact[i] = mul(fact[i - 1], i);
    for (j = 0; j <= i; j++) {
      if (j == 0)
        ncr[i][j] = 1;
      else
        ncr[i][j] = add(ncr[i - 1][j - 1], ncr[i - 1][j]);
    }
  }
  facti[MAX - 1] = power(fact[MAX - 1], mod - 2);
  for (i = MAX - 2; i >= 0; i--) {
    facti[i] = mul(facti[i + 1], i + 1);
  }
}
vector<long long> v;
long long tot = 0;
long long dp[105][MAX];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cout << setprecision(25);
  long long a, b, c, d, i, j, k;
  long long M;
  cin >> M;
  pre();
  vector<long long> cap;
  for (i = 0; i < M; i++) {
    cin >> a;
    v.push_back(a);
    tot += a;
  }
  for (i = 0; i < M; i++) cin >> a, cap.push_back(a);
  dp[0][0] = 1;
  for (i = 0; i < M; i++) {
    for (j = 0; j <= 1000; j++) {
      if (dp[i][j] == 0) continue;
      for (k = 0; k <= j + v[i]; k++) {
        long long dif = k - j;
        if (dif <= 0) {
          dif = -dif;
          if (v[i] + dif > cap[i]) continue;
          long long now = ncr[j + v[i]][v[i] + dif];
          dp[i + 1][k] = add(dp[i + 1][k], mul(dp[i][j], now));
        } else {
          long long now = ncr[j + v[i]][v[i] - dif];
          dp[i + 1][k] = add(dp[i + 1][k], mul(dp[i][j], now));
        }
      }
    }
  }
  long long ans = dp[M][0];
  ans = mul(ans, fact[tot]);
  for (auto z : v) {
    ans = mul(ans, facti[z]);
  }
  cout << ans;
  return 0;
}
