#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;
ll dp[nmax];
ll dd[nmax], xx[nmax];
ll sum[sqrt_n][sqrt_n];
struct Event {
ll type, d, i;
Event() {}
Event(ll t_, ll d_, ll i_) : type(t_), d(d_), i(i_) {}
};
vector<Event> events[nmax];
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);
// if (n >= 10000) sqrt_n_real -= 50;
for (ll i = 1; i <= n; ++ i) {
ll d, x; cin >> d >> x;
if (d == 0 || x == 0) continue;
if (d > n) continue;
if (x > n) x = n;
if (d > sqrt_n_real) {
dd[i] = d;
xx[i] = x;
} else {
ll l = i + d;
ll r = i + d * (x + 1);
if (l <= n) {
events[l].emplace_back(0, d, i);
}
if (r <= n) {
events[r].emplace_back(1, d, i);
}
}
}
for (ll d = 1; d <= sqrt_n_real; ++ d) {
sort(events[d].begin(), events[d].end(), [] (const Event& lhs, const Event& rhs) {
if (lhs.i != rhs.i) return lhs.i < rhs.i;
if (lhs.d != rhs.d) return lhs.d < rhs.d;
return lhs.type < rhs.type;
});
}
dp[1] = 1;
for (ll i = 2; i <= n; ++ i) {
if (dd[i - 1] > 0) {
ll d = dd[i - 1];
ll x = xx[i - 1];
for (ll j = 1; j <= x; ++ j) {
ll ni = i - 1 + d * j;
if (ni <= n) {
add(dp[ni], dp[i - 1]);
} else break;
}
}
for (const auto& [type, d, j] : events[i]) {
if (type == 0) {
add(sum[d][j % d], dp[j]);
} else {
sub(sum[d][j % d], dp[j]);
}
}
for (ll d = 1; d <= sqrt_n_real; ++ d) {
add(dp[i], sum[d][i % d]);
}
}
ll res = 0;
for (ll i = 1; i <= n; ++ i) {
add(res, dp[i]);
}
cout << res;
}
