def factorization(n):
    arr = []
    temp = n
    for i in range(2, int(-(-n**0.5//1))+1):
        if temp%i==0:
            cnt=0
            while temp%i==0:
                cnt+=1
                temp //= i
            arr.append((i, cnt))

    if temp!=1:
        arr.append((temp, 1))

    if arr==[]:
        arr.append((n, 1))

    return arr
import math
def pre_garner(amari, waru):
    for i in range(len(amari)):
        for j in range(i):
            g = math.gcd(waru[i], waru[j])
            if (amari[i] - amari[j])%g!=0:
                return None, None


    new_waru = [1] * len(waru)
    dicts = {}
    num_dict = {}

    # 各素数を指数が最大のとこに割りふる
    for i, wa in enumerate(waru):
        for p,beki in factorization(wa):
            if p in dicts:
                # 保存されてるpの最大の指数より大きかったらその時のindexとp^bekiを保存
                if dicts[p] < beki:
                    dicts[p] = beki
                    num_dict[p] = (i, pow(p,beki))
            else:
                dicts[p] = beki
                num_dict[p] = (i, pow(p,beki))

    for (i, num) in num_dict.values():
        new_waru[i] *= num

    # 余りを更新する
    for i in range(len(amari)):
        amari[i] %= new_waru[i]
        
    return amari, new_waru

def GANER_ALGORYTHM(amari, waru, MOD=10**9+7):
    waru.append(MOD)
    coeff = [1] * len(waru)
    constant = [0] * len(waru)

    for i in range(len(amari)):
        t = (((amari[i] - constant[i])% waru[i]) * pow(coeff[i], -1, waru[i])) % waru[i]
        for j in range(len(waru)):
            constant[j] = (constant[j] + t*coeff[j])%waru[j]
            coeff[j] = (coeff[j]*waru[i]) % waru[j]

    return constant
def oi(): return int(input())
def os(): return input()
def mi(): return list(map(int, input().split()))

# import sys
# input = sys.stdin.readline
# import sys
# sys.setrecursionlimit(10**8)
# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')
# input_count = 0

input_count = 0
N = oi()
amari = []
wari = []
all_zero = True
for _ in range(N):
    x,y = mi()
    wari.append(y)
    amari.append(x)
    if x != 0:
        all_zero = False
if all_zero:
    amari, wari = pre_garner(amari, wari)
    out = 1
    for w in wari:
        out = (out*w)%(10**9+7)
    print(out)
else:
    amari, wari = pre_garner(amari, wari)
    if amari is None:
        print(-1)
    else:
        out = GANER_ALGORYTHM(amari, wari)
        print(out[-1])