#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
#define pb push_back
#define pf push_front
#define fi first
#define se second
const ll mod = 1e9+7, mxn = 1e5+7, block = 320;
ll dp[mxn], d[mxn], x[mxn], n;
signed main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll n; cin >> n; dp[1] = 1;
for (ll i = 1; i <= n; i++)
{
cin >> d[i] >> x[i];
if (d[i] && x[i] <= block)
{
for (ll j = i+d[i]; j <= min(n, i+x[i]*d[i]); j += d[i])
{
dp[j] += dp[i];
dp[j] %= mod;
}
}
}
vector<pair<ll,pair<ll,ll>>> v;
for (ll i = 1; i <= n; i++)
{
for (pair<ll,pair<ll,ll>> j : v) if ((i-j.fi)%j.se.fi == 0 && (i-j.fi)/j.se.fi <= j.se.se)
{
dp[i] += dp[j.fi];
dp[i] %= mod;
}
if (d[i] && x[i] > block) v.pb({i,{d[i],x[i]}});
}
ll ans = 0;
for (ll i = 1; i <= n; i++)
{
ans += dp[i];
ans %= mod;
}
cout << ans;
}
