#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
const int maxn = 1e5 + 10;
int x[maxn];
int d[maxn];
int delm = ceil(sqrt(maxn));
int dp[maxn];
vector<vector<int>> resp(maxn, vector<int>(delm + 2, -1));
int n;
int sum (int a, int b) {
return (((a + b) % mod) + mod) % mod;
}
int aux(int i, int d) {
if (d == 0) return 0;
if (i >= n) return 0;
if (i == n - 1) return 1;
if (resp[i][d] != -1) return resp[i][d];
int ans = sum(dp[i], aux(i + d, d));
return resp[i][d] = ans;
}
signed main () {
cin.tie(0);
ios_base::sync_with_stdio(0);
cout.tie(0);
cin >> n;
for (int i = 0; i < n; i++) {
cin >> d[i] >> x[i];
}
dp[n - 1] = 1;
for (int i = n - 2; i >= 0; i--) {
if (d[i] <= delm) {
long long thing = (long long)(x[i] + 1) * (long long)(d[i]);
int t1 = aux(i + d[i], d[i]);
int t2 = 0; if (i + thing < n) t2 = aux(i + thing, d[i]);
dp[i] = sum(1 + t1, -t2);
} else {
dp[i] = 1;
for (int j = i + d[i], amt = 1; amt <= x[i]; j += d[i], amt++) {
dp[i] = sum(dp[i], dp[j]);
}
}
}
for (int i = 0; i < 1; i++) {
cout << dp[i] << ' ';
}
}
