import sys
#input = sys.stdin.readline #文字列につけてはダメ
input = sys.stdin.buffer.readline #文字列につけてはダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
#from collections import defaultdict 
#from collections import deque
#import copy
#import math
#from functools import lru_cache
#@lru_cache(maxsize=None)
MOD = pow(10,9) + 7
#MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]


def main():
    L = int(input())
    ans = 1
    for i in range(L):
        p,e = map(int,input().split())
        inv = pow(1-p,MOD-2,MOD)
        #print(inv)
        x = e+1 - p*(1 - pow(p,e,MOD)) * inv - pow(p,e+1,MOD)
        #print(e+1, p*(1 - pow(p,e,MOD)), pow(p,e+1))
        x %= MOD
        #print(x)
        x *= inv
        ans *= x%MOD
        ans %= MOD
    print(ans)


if __name__ == '__main__':
    main()