mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    L = int(input())
    ans = 1
    for _ in range(L):
        p, e = map(int, input().split())
        inv = pow(p - 1, mod - 2, mod)
        tmp = inv * (inv * (pow(p, e + 2, mod) - 1) - (e + 2))%mod
        ans = (ans * tmp)%mod
    print(ans)


if __name__ == '__main__':
    main()