#include <bits/stdc++.h>
#ifdef LOCAL
#include "/home/trcmai/code/tools.h"
#define debug(x...) \
cerr << "\e[91m" << __func__ << ":" << __LINE__ << " [" << #x << "] = ["; \
_print(x); \
cerr << "\e[39m" << endl;
#else
#define debug(x...)
#endif
using namespace std;
#define all(a) a.begin(), a.end()
#define fi first
#define se second
#define ll long long
#define endl '\n'
const int N = 2e5 + 6, LOG = 27, MOD = 1e9 + 7;
const ll INF = 1e18;
int n;
ll dp[N], d[N], x[N];
const int BS = 350;
ll sum[N][BS + 10];
signed main()
{
cin.tie(0)->sync_with_stdio(0);
auto solver = [&]() {
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] > BS) {
for (int j = 1; j <= x[i]; ++j) {
if (i + d[i] * j > n) break;
dp[i] = (dp[i] + dp[i + j*d[i]])%MOD;
}
}
if (d[i] <= BS && d[i] > 0 && x[i] > 0) {
dp[i] = (dp[i] + sum[i + d[i]][d[i]])%MOD;
if (i + (x[i] + 1) * d[i] <= n)
dp[i] = (dp[i] - sum[i + (x[i]+1)*d[i]][d[i]])%MOD;
}
dp[i] = (dp[i] + MOD)%MOD;
for (int j = 1; j <= BS; ++j)
sum[i][j] = (sum[i + j][j] + dp[i])%MOD;
}
cout << dp[1] << endl;
};
int t = 1; // cin>>t;
while (t--)
solver();
}
