mod = 10 ** 9 + 7
L = int(input())
ans = 1
for _ in range(L):
    p, e = map(int, input().split())
    # a(p^e) = (p*(p^(e+1)-1)-(p-1)*(e+1))/(p-1)^2
    numer = (p * (pow(p, e + 1, mod) - 1) - (p - 1) * (e + 1)) % mod
    ans = ans * numer % mod * pow(p - 1, mod - 3, mod) % mod
print(ans)