#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
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<int>> a(n + 2 * T + 1 ,vector<int>(T + 1));
vector<int> dp(n + 2 *T + 1);
for(int i = n ;i >= 1 ; i--){
if(se[i].first == 0)dp[i] = 1;
else{
if(se[i].first <= T){
dp[i] = a[i + se[i].first][se[i].first] + 1;
if(i + se[i].first * (se[i].second + 1) <= n)
dp[i] = (dp[i] - a[i + se[i].first * (se[i].second + 1)][se[i].first] + MOD ) % MOD;
}
else{
dp[i] = 1;
for(int j = i + se[i].first; j <= min(n , i + se[i].first * se[i].second) ; j += se[i].first){
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';
}
