#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint1000000007;
using namespace std;
#define rep1(a)          for(int64_t i = 0; i < a; i++)
#define rep2(i, a)       for(int64_t i = 0; i < a; i++)
#define rep3(i, a, b)    for(int64_t i = a; i < b; i++)
#define rep4(i, a, b, c) for(int i = a; i < b; i += c)
#define overload4(a, b, c, d, e, ...) e
#define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__)
const int64_t MOD=1000000007;
const long long INF = 1LL<<60;

int main(){
  mint ans=1;
  int L;cin>>L;
  rep(L){
    int64_t P,E;cin>>P>>E;
    mint temp=P*(pow_mod(P,E+1,MOD)-1);
    temp/=P-1;
    temp-=E+1;
    temp/=P-1;
    ans*=temp;
  }
  cout<<ans.val();
}