#include<bits/stdc++.h>
#define int long long
#define MAXN (int)1e5+5
#define MAXS 320
using namespace std;
const int mod=1e9+7;
int d[MAXN],x[MAXN],p[MAXN][MAXS],dp[MAXN];
void solve() {
int n;cin>>n;
for(int i=1;i<=n;i++){
cin>>d[i]>>x[i];
dp[i]=1;
}
for(int j=1;j*j<=n;j++){
p[n][j]=1;
}
for(int i=n-1;i>=1;i--){
if(d[i]){
if(d[i]*d[i]<=n){
if(i+d[i]<=n){
dp[i]+=(p[i+d[i]][d[i]]-p[min(i+(x[i]+1)*d[i],n+1)][d[i]]+mod)%mod;
dp[i]%=mod;
}
}else{
for(int j=1;j<=x[i]&&i+j*d[i]<=n;j++){
dp[i]=(dp[i]+dp[i+j*d[i]])%mod;
}
}
}
for(int j=1;j*j<=n;j++){
p[i][j]=dp[i]+(i+j<=n?p[i+j][j]:0ll);
}
}
cout<<dp[1]<<'\n';
}
int32_t main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int32_t T=1;//cin>>T;
while(T--) {
solve();
}
return 0;
}
