# https://qiita.com/AkariLuminous/items/3e2c80baa6d5e6f3abe9#4-floor_sum mod = 10**9 + 7 def floor_sum(n, m, a, b): ans = 0 while True: if a >= m or a < 0: ans += n * (n - 1) * (a // m) // 2 ans %= mod a %= m if b >= m or b < 0: ans += n * (b // m) ans %= mod b %= m y_max = a * n + b if y_max < m: break n, b, m, a = y_max // m, y_max % m, a, m return ans N = int(input()) M = int(input()) A = list(map(int, input().split())) B = list(map(int, input().split())) ans = 0 for a in A: for b in B: ans += floor_sum(b + 1, b, a, 0) * 2 ans %= mod print(ans)