#include <iostream>
#include <vector>
using namespace std;
typedef long long ll;
# define d first
# define x second
const ll mod = 1e9 + 7, N = 2e5;
ll acc[400][400], add[N][400], n, d[N], x[N], dp[N];
void f(ll i, ll d, ll a) {
if (i >= n) return;
if (a < 0) a = (a + mod) % mod;
add[i][d] = (add[i][d] + a) % mod;
}
void solve() {
cin >> n;
for (ll i = 0; i < n; i++) cin >> d[i] >> x[i];
dp[0] = 1;
for (ll i = 0; i < n; i++) {
for (ll j = 1; j < 400; j++) {
ll m = i % j;
acc[j][m] = (acc[j][m] + add[i][j]) % mod;
dp[i] = (dp[i] + acc[j][m]) % mod;
}
if (d[i] == 0) continue;
if (d[i] < 400) {
ll j = d[i];
f(i + j, j, dp[i]);
f(i + j * x[i] + j, j, -dp[i]);
} else {
for (ll j = i + d[i], xu = 1; xu <= x[i] && j < n; xu++, j += d[i]) {
dp[j] = (dp[j] + dp[i]) % mod;
}
}
}
ll ans = 0;
for (ll i = 0; i < n; i++) (ans += dp[i]) %= mod;
cout << ans % mod;
}
int main() {
//freopen("filename.in", "r", stdin), freopen("filename.out", "w", stdout);
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int t = 1; //cin >> t;
while (t--) solve();
}
