#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
const long nPrime = 1000000007;
//const long nPrime = 998244353;
typedef long long ll;
const long long nMod = nPrime;
class ModInt {
    long long x;
public:
    ModInt(long long x=0) : x((x%nMod+nMod)%nMod) {}
    ModInt operator-() const { 
      return ModInt(-x);
    }
    ModInt& operator+=(const ModInt& a) {
        if ((x += a.x) >= nMod) x -= nMod;
        return *this;
    }
    ModInt& operator-=(const ModInt& a) {
        if ((x += nMod-a.x) >= nMod) x -= nMod;
        return *this;
    }
    ModInt& operator*=(const  ModInt& a) {
        (x *= a.x) %= nMod;
        return *this;
    }
    ModInt operator+(const ModInt& a) const {
        ModInt res(*this);
        return res+=a;
    }
    ModInt operator-(const ModInt& a) const {
        ModInt res(*this);
        return res-=a;
    }
    ModInt operator*(const ModInt& a) const {
        ModInt res(*this);
        return res*=a;
    }
    ModInt Pow(long long t) const {
        if (!t) return 1;
        ModInt a = Pow(t>>1);
        a *= a;
        if (t&1) a *= *this;
        return a;
    }
    // for prime nMod
    ModInt Inv() const {
        return Pow(nMod-2);
    }
    ModInt& operator/=(const ModInt& a) {
        return (*this) *= a.Inv();
    }
    ModInt operator/(const ModInt& a) const {
        ModInt res(*this);
        return res/=a;
    }

    friend ostream& operator<<(ostream& os, const ModInt& m){
        os << m.x;
        return os;
    }
};

void MakeTable(vector<ModInt> &viInv, vector<ModInt> &viFctr,
               vector<ModInt> &viFctrInv, bool bUseFctr = false,
               const long nTableSize = 1000000){
    
    viInv.resize(nTableSize+1, 1);
    for(long i = 1; i < nTableSize+1; i++){
        viInv[i] /= i;            
    }
    if(!bUseFctr){
        return;
    }
  
    viFctr.resize(nTableSize+1, 1);
    viFctrInv.resize(nTableSize+1, 1);
    for(long i = 1; i < nTableSize+1; i++){
        viFctr[i] = viFctr[i-1] * i;         
    }
    viFctrInv[nTableSize] /= viFctr[nTableSize];
    for(long i = nTableSize; i >= 1; i--){
        viFctrInv[i-1] = viFctrInv[i]*i;
    }
}
int main() {
    long n;
    cin >> n;
    ModInt nAns = 1;
    for(long i = 0; i < n; i++){
        long p,e;
        cin >> p >> e;
        ModInt pm = p,em = e;
        ModInt S1 = (em+1);
        S1 *= ((pm.Pow(e+1)-1)/(pm-1));
        ModInt S2 = 1;
        S2 /= (ModInt(1)-pm);
        S2 *= ((pm.Pow(e+1)-p)/(pm-1) - em*pm.Pow(e+1));
        nAns *= (S1-S2);
    }
    
    cout << nAns <<endl;
    return 0;
}