#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e5;
const long long mod = 1e9 + 7;
int n;
long long d[maxn + 1], x[maxn + 1];
bool check3 = true, check4 = true;
namespace sub2{
long long dp[10001];
void solve() {
dp[1] = 1;
long long res = 0;
for (int i = 1; i <= n; ++i){
res = (res + dp[i]) % mod;
if (d[i] == 0) continue;
for (int j = 1; j <= x[i]; ++j){
if (i + d[i] * j > n) break;
dp[i + d[i] * j] = (dp[i + d[i] * j] + dp[i]) % mod;
}
}
cout << res << '\n';
return;
}
}
namespace sub3{
long long dp[maxn + 1], dif[maxn + 1];
void solve(){
long long res = 0;
dif[1] = 1;
dif[2] = -1;
for (int i = 1; i <= n; ++i){
dp[i] = (dp[i - 1] + dif[i]);
res = (res + dp[i]);
int st = i + 1, en = i + x[i] + 1;
if (en > st && st <= n){
dif[st] = (dif[st] + dp[i]);
if (en <= n)
dif[en] = (dif[en] - dp[i]);
}
}
cout << res << '\n';
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n;
for (int i = 1; i <= n; ++i){
cin >> d[i] >> x[i];
if (d[i] != 1) check3 = false;
if (x[i] != 1e9) check4 = false;
}
if (n <= 1e4){
sub2::solve();
}
else if (check3){
sub3::solve();
}
return 0;
}
