#include <bits/stdc++.h>
#define all(x) (x).begin(),(x).end()
#define pb push_back
#define int long long
using namespace std;
int mod=1e9+7;
signed main(){
ios::sync_with_stdio(false);
cin.tie(NULL);
int n; cin >> n;
vector<int> d(n+1), x(n+1);
for(int i=1; i<=n; i++){
cin >> d[i] >> x[i];
}
int resp=0;
vector<int> r(n+1);
for(int i=n; i>=1; i--){
if(d[i]!=0){
for(int j=i; j<=n&&j<=x[i]*d[i]+i; j+=d[i]){
r[i]=(r[i]+r[j])%mod;
// cout << i << ": "<<j<<endl;
}
}
r[i]++;
r[i]%=mod;
// cout << i << " "<<r[i]<<endl;
// resp=(resp+r[i])%mod;
}
cout << r[1]<<endl;
}
