#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#define int long long int
using namespace std;
typedef long long ll;
const int T = 350;
const int MOD = 1e9 + 7;
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n; cin >> n;
vector<pair<int , int >> se(n + 1);
for(int i = 1 ; i <= n ; i++){
cin >> se[i].first >> se[i].second;
}
vector<vector<ll>> a(n + 2*T + 1, vector<ll>(T + 1, 0));
vector<ll> dp(n + 2*T + 1, 0);
for(int i = n; i >= 1; i--){
ll f = se[i].first;
ll s = se[i].second;
if(f == 0){
dp[i] = 1;
}
else if(f <= T){
dp[i] = 1 + a[i + f][f];
if(i + se[i].first * (se[i].second + 1) <= n) dp[i] -=a[i + f*(s+1)][f];
dp[i] = (dp[i] % MOD + MOD) % MOD;
}
else {
dp[i] = 1;
for(int j = i + f; j <= min(n, i + f*s); j += f){
dp[i] = (dp[i] + dp[j]) % MOD;
}
}
for(int j = 1; j <= T; j++){
a[i][j] = (a[i + j][j] + dp[i]) % MOD;
}
}
cout << dp[1] << "\n";
}
