#include <bits/stdc++.h>
using namespace std;
#define int long long
const int m = 1e9 + 7;
int n, dp[100005];
pair<int, int> a[100005];
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
unordered_map<int, int> rem[100005];
int32_t main() {
ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> n;
for (int i = 1; i <= n; i++) cin >> a[i].first >> a[i].second;
dp[1] = 1;
bool b = 1;
for (int i = 1; i <= n; i++) if (a[i].first != 1) b = 0;
if (n <= 1) {
for (int i = 2; i <= n; i++) {
for (int j = 1; j < i; j++) {
if (a[j].first == 0) continue;
int d = i - j;
if (d % a[j].first == 0
&& (d / a[j].first) <= a[j].second)
dp[i] = (dp[i] + dp[j]) % m;
}
}
} else if (b) {
int sum = 1;
pq.emplace(a[1].second + 1, 1);
for (int i = 2; i <= n; i++) {
while (!pq.empty() && pq.top().first < i) {
sum = (sum + m - pq.top().second) % m;
pq.pop();
}
dp[i] = sum;
sum = (sum + dp[i]) % m;
pq.emplace(i + a[i].second, dp[i]);
}
} else {
vector<int> v;
unordered_map<int, int> tmp;
for (int i = 1; i <= n; i++) {
if (tmp.find(a[i].first) == tmp.end()) {
tmp[a[i].first] = v.size();
v.push_back(a[i].first);
}
}
rem[0][1 % a[1].first] = 1;
for (int i = 2; i <= n; i++) {
for (int idx = 0; idx < v.size(); idx++) {
int md = v[idx];
int r = i % md;
dp[i] = (dp[i] + rem[idx][r]) % m;
}
int idx = v[a[i].first];
int r = i % a[i].first;
rem[idx][r] = (rem[idx][r] + dp[i]) % m;
}
}
int ans = 0;
for (int i = 1; i <= n; i++) ans = (ans + dp[i]) % m;
cout << ans;
}
