#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ii pair<int,int>
#define fir first
#define sec second
#define pb push_back
#pragma GCC optimize("O3,unroll-loops")
const int mod=1e9+7,maxn=1e5,blk=350;
int sum[maxn+blk][blk+1];
int dp[maxn+2];
signed main(){
int n; cin>>n;
int d[n+1],x[n+1];
for(int q=1;q<=n;q++){
cin>>d[q]>>x[q];
}
int ans=0;
for(int q=n;q>=1;q--){
if(d[q]>=blk){
int tot=0;
for(int w=q+d[q];w<=min(n,q+(x[q]*d[q]));w+=d[q]){
tot+=dp[w];tot%=mod;
}
dp[q]=tot;
}
else{
int tot=sum[q+d[q]][d[q]];
int lst=q+(x[q]+1)*d[q];
if(lst<=n){
tot-=sum[lst][d[q]];
}
tot%=mod; tot=(tot+mod)%mod;
dp[q]=tot;
}
dp[q]++;
for(int w=1;w<=blk;w++){
sum[q][w]=sum[q+w][w]+dp[q];
sum[q][w]%=mod;
}
}
cout<<dp[1]<<endl;
}
