#include <cstdio>
#include <stdio.h>
#include <stdbool.h>
#include <iostream>
#include <map>
#include <vector>
#include <climits>
#include <stack>
#include <string>
#include <queue>
#include <algorithm>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <cctype>
#include <bitset>
#include <iomanip>
#include <cstring>
#include <numeric>
#include <cassert>
using namespace std;
#define int long long
#define pii pair<int, int>
#define mp make_pair
#define pb push_back
#define fi first
#define se second
const int BLK = 300;
const int MOD = 1000000007;
int32_t main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n;
cin>>n;
vector<int> dp(n+2, 0);
vector<pii> vect(n+1);
vector<vector<vector<int> > > s(BLK, vector<vector <int> >(BLK, {0}));
for (int i=1; i<=n; ++i)cin>>vect[i].fi>>vect[i].se;
for (int i=n; i>=1; --i){
dp[i]=1;
if (vect[i].fi>=BLK)for (int j=1; j<=vect[i].se&&i+j*vect[i].fi<=n; ++j)dp[i]=(dp[i]+dp[i+j*vect[i].fi])%MOD;
else if (vect[i].fi){
dp[i]=(dp[i]+s[vect[i].fi][i%vect[i].fi].back())%MOD;
//cout<<"{"<<s[vect[i].fi][i%vect[i].fi][max((int)s[vect[i].fi][i%vect[i].fi].size()-vect[i].se, 0ll)]<<"}\n";
//cout<<"["<<i<<" "<<s[vect[i].fi][i%vect[i].fi].back()<<" "<<s[vect[i].fi][i%vect[i].fi].size()<<" "<<vect[i].se<<" "<<max((int)s[vect[i].fi][i%vect[i].fi].size()-vect[i].se, 0ll)<<"]\n";
dp[i]=(dp[i]+MOD-s[vect[i].fi][i%vect[i].fi][max((int)s[vect[i].fi][i%vect[i].fi].size()-vect[i].se-1, 0ll)])%MOD;
}
for (int j=1; j<BLK; ++j)s[j][i%j].pb((dp[i]+s[j][i%j].back())%MOD);
}
//cout<<"[";
//for (int i=1; i<=n; ++i)cout<<dp[i]<<" ";
//cout<<"]\n";
cout<<dp[1];
}
