#include<bits/stdc++.h>
using namespace std;
using ll = int32_t;
constexpr size_t nmax = 100000 + 15;
constexpr size_t sqrt_n = 317 + 15;
constexpr ll mod = 1'000'000'000 + 7;
void add(ll& lhs, ll rhs) {
lhs += rhs;
if (lhs >= mod) lhs -= mod;
}
void sub(ll& lhs, ll rhs) {
lhs -= rhs;
if (lhs < 0) lhs += mod;
}
ll n;
set<ll> from[nmax];
ll dp[nmax];
ll sum[sqrt_n][sqrt_n];
struct Event {
ll type, i;
Event() {}
Event(ll t_, ll i_) : type(t_), i(i_) {}
};
vector<Event> events[nmax][sqrt_n];
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr); std::cout.tie(nullptr);
cin >> n;
ll sqrt_n_real = sqrt(n);
for (ll i = 1; i <= n; ++ i) {
ll d, x; cin >> d >> x;
if (d == 0 || x == 0) continue;
if (x > n) x = n;
if (d > sqrt_n_real) {
for (ll j = 1; j <= x; ++ j) {
ll new_i = i + d * j;
if (new_i > n) break;
from[new_i].insert(i);
}
} else {
ll l = i + d;
ll r = i + d * (x + 1);
if (l <= n) {
events[l][d].emplace_back(0, i);
}
if (r <= n) {
events[r][d].emplace_back(1, i);
}
}
}
dp[1] = 1;
for (ll i = 2; i <= n; ++ i) {
for (const auto& j : from[i]) {
add(dp[i], dp[j]);
}
for (ll d = 1; d <= sqrt_n_real; ++ d) {
for (const auto& [type, j] : events[i][d]) {
if (type == 0) {
add(sum[d][j % d], dp[j]);
} else {
sub(sum[d][j % d], dp[j]);
}
}
add(dp[i], sum[d][i % d]);
}
}
ll res = 0;
for (ll i = 1; i <= n; ++ i) {
add(res, dp[i]);
}
cout << res;
}
