#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define f first
#define s second
#define pb push_back
#define ep emplace
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define uniquev(v) sort(all(v)), (v).resize(unique(all(v)) - (v).begin())
#define mem(f,x) memset(f , x , sizeof(f))
#define sz(x) (ll)(x).size()
#define __lcm(a, b) (1ll * ((a) / __gcd((a), (b))) * (b))
#define mxx *max_element
#define mnn *min_element
#define cntbit(x) __builtin_popcountll(x)
#define len(x) (int)(x.length())
const int N = 3e5 + 10;
int d[N], x[N], dp[N], mod = 1e9 + 7;
ll solve() {
int n;
cin >> n;
for (int i = 1; i <= n; i++)
cin >> d[i] >> x[i];
for (int i = n; i >= 1; i--) {
dp[i] = 1;
if (d[i] == 0)
continue;
for (int j = 1; j <= x[i] && j * d[i] + i <= n; j++) {
dp[i] = (dp[i] + dp[j * d[i] + i]) % mod;
}
}
return dp[1];
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
//cin >> t;
while (t--) {
cout << solve() << '\n';
}
return 0;
}
