#include <bits/stdc++.h>
using namespace std;
using i64=long long int;
int main(){
i64 kor=400;
i64 mod=1e9+7;
i64 n;
cin >> n;
vector<i64> comb(n,0);
vector<vector<i64>> kolzbr(kor,vector<i64>(kor,0));
vector<vector<i64>> kolzbrmak(n,vector<i64>(kor,0));
i64 rje=0;
comb[0]=1;
for (i64 i=0;i<n;i++){
i64 unos;
i64 unos2;
cin >> unos >> unos2;
//cout << "a\n";
for (i64 j=1;j<kor;j++){
i64 pom=i%j;
// cout << i << " " << j << " " << pom << "\n";
// cout << kolzbr[j][pom] << " " << kolzbrmak[i][j] << "\n";
comb[i]+=kolzbr[j][pom];
comb[i]%=mod;
kolzbr[j][pom]+=kolzbrmak[i][j];
kolzbr[j][pom]%=mod;
}
//cout << "b\n";
if (unos*unos2==0){
// cout << comb[i] << "\n";
rje+=comb[i];
rje%=mod;
continue;
}
if (unos>=kor){
i64 kol=0;
for (i64 j=i+unos;j<n && kol<unos2;j+=unos,kol++){
// cout << i << " " << j << "-=-\n";
comb[j]+=comb[i];
comb[j]%=mod;
}
}
else {
i64 indkra=i+unos*unos2;
if (indkra<n){
kolzbrmak[indkra][unos]-=comb[i];
kolzbrmak[indkra][unos]+=mod;
kolzbrmak[indkra][unos]%=mod;
}
kolzbr[unos][i%unos]+=comb[i];
kolzbr[unos][i%unos]%=mod;
}
//cout << "c\n";
// cout << comb[i] << "\n";
rje+=comb[i];
rje%=mod;
}
cout << rje << "\n";
}
