import sys,random,bisect
from collections import deque,defaultdict
from heapq import heapify,heappop,heappush
from itertools import permutations
from math import log,gcd

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

mod = 10**9 + 7

L = int(input())
res = 1
for _ in range(L):
    p,e = mi()

    ip = pow(p-1,mod-2,mod)
    res *= ip * (((p*(pow(p,e+1,mod)-1)%mod)*ip % mod)-(e+1)) % mod
    #print(ip * (((p*(pow(p,e+1,mod)-1)%mod)*ip % mod)-(e+1)))
    res %= mod

print(res)