#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define rep(i, n) for(ll i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
const ll MOD = 1000000007;
ll mpow(ll x, ll y){
    ll res = 1; x %= MOD;
    while(y){
        if(y%2) res = res * x % MOD;
        x = x * x % MOD;
        y /= 2;
    }
    return res;
}
int main(){
    ll l,ans = 1;
    cin >> l;
    rep(i,l){
        ll r,n;
        cin >> r >> n;
        n++;
        ll x = mpow(r-1, MOD-2);
        ans = ans * ((r * (mpow(r,n) - 1) % MOD * x % MOD - n + MOD) * x % MOD) % MOD;
    }
    cout << ans << endl;
    return 0;
}