#include <bits/stdc++.h>
using namespace std;
long long n, k, res = 1;
long long a[100005];
long long b[100005];
long long d = 1, ans;
int main() {
  cin >> n >> k;
  for (int i = 0; i < k; i++) d *= 10;
  for (int i = 0; i < n / k; i++) cin >> a[i];
  for (int i = 0; i < n / k; i++) cin >> b[i];
  for (int i = 0; i < n / k; i++) {
    ans = (d - 1) / a[i] + 1;
    if (b[i] == 0)
      ans -= ((d / 10) - 1) / a[i] + 1;
    else
      ans -=
          ((b[i] + 1) * (d / 10) - 1) / a[i] - ((b[i]) * (d / 10) - 1) / a[i];
    res = (res * ans) % (1000000007);
  }
  cout << res;
  return 0;
}
