#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using ll = long long;
#define ordered_set tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define ordered_multiset tree<int, null_type, less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
//const ll MOD = 998244353LL;
const ll MOD = 1e9 + 7;
template<const ll MOD> struct Modular {
static const ll mod = MOD;
ll v; explicit operator ll() const { return v; }
Modular():v(0) {}
Modular(ll _v) { v = ll((-MOD < _v && _v < MOD) ? _v : _v % MOD); if (v < 0) v += MOD; }
friend Modular mpw(Modular a, ll p) {
Modular ans = 1;
for (; p; p /= 2, a *= a) if (p&1) ans *= a;
return ans; }
friend Modular inv(const Modular& a) { return mpw(a,MOD-2);}
friend bool operator!=(const Modular& a, const Modular& b) { return !(a == b); }
friend bool operator<(const Modular& a, const Modular& b) { return a.v < b.v; }
Modular& operator+=(const Modular& o) { if ((v += o.v) >= MOD) v -= MOD; return *this; }
Modular& operator-=(const Modular& o) { if ((v -= o.v) < 0) v += MOD; return *this; }
Modular& operator*=(const Modular& o) { v = ll((ll)v*o.v%MOD); return *this; }
Modular& operator/=(const Modular& o) { return (*this) *= inv(o); }
Modular operator-() const { return Modular(-v); }
Modular& operator++() { return *this += 1; }
Modular& operator--() { return *this -= 1; }
friend Modular operator+(Modular a, const Modular& b) { return a += b; }
friend Modular operator-(Modular a, const Modular& b) { return a -= b; }
friend Modular operator*(Modular a, const Modular& b) { return a *= b; }
friend Modular operator/(Modular a, const Modular& b) { return a /= b; }
friend istream& operator>>(istream& inp, Modular& a) { ll x; inp >> x; a = Modular(x); return inp;}
friend ostream& operator<<(ostream& out, const Modular& a) { out << a.v; return out; }
};
using Mint = Modular<MOD>;
void solve() {
int n;
cin >> n;
vector<int> s(n), l(n);
for(int i = 0; i < n; i++)
cin >> s[i] >> l[i];
int bs = max((int)sqrt(n), 1);
vector<Mint> dp(n + 1, Mint(0));
vector<vector<Mint>> pref(bs, vector<Mint>(n + 1, Mint(0)));
dp[1] = Mint(1);
for(int i = 1; i <= n; i++) {
Mint cur = dp[i];
for(int j = 1; j < bs; j++) {
if(i - j > 0)
pref[j][i] += pref[j][i - j];
cur += pref[j][i];
}
dp[i] = cur;
int hop = s[i - 1], bound = l[i - 1];
ll lo = i + hop, hi = min((ll)n, (ll)i + (ll)hop * (ll)bound);
if(lo > n)
continue;
if(hop < bs) {
pref[hop][lo] += dp[i];
if(hi + hop <= n)
pref[hop][hi + hop] -= dp[i];
} else {
for(int j = lo; j <= hi; j += hop)
dp[j] += dp[i];
}
}
Mint ans = 0;
for(auto &x : dp)
ans += x;
cout << ans << '\n';
}
int main() {
int t = 1;
// cin >> t;
while(t--)
solve();
}
