MOD = 10 ** 9 + 7

l = int(input())
ans = 1
for _ in range(l):
  pi, ei = map(int, input().split())
  cnt = (pow(pi, ei + 2, MOD) - pi - (pi - 1) * (ei + 1)) % MOD
  cnt = (cnt * pow(pi - 1, 2 * (MOD - 2), MOD)) % MOD
  ans = (ans * cnt) % MOD

print(ans)