#include <bits/stdc++.h>
using namespace std;
#define int long long
const int mod = 1e9+7;
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
int n;
cin >> n;
int sq = ceil(sqrt(n));
int laz[sq][sq];
for(int i = 0;i<sq;i++){
fill(laz[i],laz[i]+sq,0);
}
vector<array<int,3>>rem[n];
long long dp[n];
fill(dp,dp+n,0);
dp[0]=1;
for(int i = 0;i<n;i++){
int d,x;
cin >> d >> x;
long long curr = 0;
for(int j = 0;j<sq;j++){
///j=0 corresponds to j+1.
curr+=laz[j][(i%(j+1))];
curr%=mod;
}
dp[i]+=curr;
dp[i]%=mod;
///first take care of rem.
for(array<int,3>a:rem[i]){
laz[a[0]][a[1]]-=a[2];
laz[a[0]][a[1]]%=mod;
}
///now put this somewhere
if(d&&x){
if(d<sq){
///do lazy ENSURE to add to rem as well
int las = i+(d*x);
las=min(las,n-1);
laz[d-1][i%d]+=dp[i];
rem[las].push_back({d-1,i%d,dp[i]});
}
else{
///just bruteforce
for(int j = 1;j<=x;j++){
int ind = i+d*j;
if(ind>=n)
break;
dp[ind]+=dp[i];
dp[ind]%=mod;
}
}
}
}
long long ans = 0;
for(int i = 0;i<n;i++){
ans+=dp[i];
ans%=mod;
}
ans+=mod;
ans%=mod;
cout << ans;
return 0;
}
