#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vi vector<ll>
#define vvi vector<vector<ll>>
#define vs vector<string>
#define vc vector<char>
#define vb vector<bool>
#define vp vector<pair<ll, ll>>
#define vpp vector<pair<ll, pair<ll, ll>>>
#define pp pair<ll, ll>
#define qi queue<ll>
#define qp queue<pp>
#define pqi priority_queue<ll>
#define pqp priority_queue<pp>
#define mi map<ll, ll>
#define mpi map<pp, ll>
#define mip map<ll, pp>
#define mp map<pp, pp>
#define mb map<ll, bool>
#define si set<ll>
#define sp set<pp>
#define sc set<char>
#define mod 1000000007
#define inf 1000000000000000000
#define all(x) (x).begin(), (x).end()
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
ll n;
cin >> n;
vi d(n + 1), x(n + 1);
for(int i = 1; i <= n; i++) cin >> d[i] >> x[i];
ll LIM = sqrt(n);
vi dp(n + 1, 0);
dp[1] = 1;
vvi add(LIM);
for(int i = 1; i < LIM; i++) {
add[i] = vi(i, 0);
}
vector<vector<pair<pp, ll>>> ends(n + 1);
for(int i = 1; i <= n; i++) {
for(int j = 1; j < LIM; j++) {
ll rem = i % j;
dp[i] = (dp[i] + add[j][rem]) % mod;
}
for(auto[t, val] : ends[i]) {
auto[div, rem] = t;
add[div][rem] = (mod + add[div][rem] - val) % mod;
}
if(d[i] == 0) continue;
if(d[i] >= LIM) {
for(int j = 1; j <= x[i]; j++) {
ll stop = i + d[i] * j;
if(stop > n) break;
dp[stop] += dp[i];
dp[stop] %= mod;
}
}
else {
ll rem = i % d[i];
add[d[i]][rem] = (add[d[i]][rem] + dp[i]) % mod;
ll last = i + d[i] * x[i];
if(last > n) continue;
ends[last].push_back({{d[i], rem}, dp[i]});
}
}
ll ans = 0;
for(int i = 1; i <= n; i++) ans = (ans + dp[i]) % mod;
cout << ans << '\n';
return 0;
}
