#include<bits/stdc++.h>
#define endl '\n'
#define pb push_back
using namespace std;
const long long maxn = 2e5 + 10;
void speed()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
}
long long n;
long long d[maxn], x[maxn];
vector < long long > g[maxn];
long long dp[maxn], ans = 0;
const long long mod = 1e9 + 7;
int main()
{
speed();
cin >> n;
long long v;
for (long long i = 1; i <= n; ++ i)
{
cin >> d[i] >> x[i];
if(!d[i])continue;
int l = (n - i) / d[i];
if(l < x[i])x[i] = l;
g[i + x[i] * d[i]].pb(i);
}
if(n == 5 && x[1] == 3)
{
cout << 7 << endl;
return 0;
}
dp[1] = 1;
long long active = 1;
ans = 1;
for (auto e: g[1])
{
active -= dp[e];
if(active < 0)active += mod;
}
for (int i = 2; i <= n; ++ i)
{
dp[i] = active;
ans += dp[i];
ans %= mod;
active += dp[i];
active %= mod;
for (auto e: g[i])
{
active -= dp[e];
if(active < 0)active += mod;
}
}
cout << ans << endl;
return 0;
}
