#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,fma")
#define ll long long
#define pb push_back
#define eb emplace_back
#define pu push
#define ins insert
#define bruh ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define ff(x,a,b,c) for (auto x=a;x<=b;x+=c)
#define fd(x,a,b,c) for (auto x=a;x>=b;x-=c)
#define int ll
using namespace std;
//mt19937 mt(chrono::steady_clock::now().time_since_epoch().count());
typedef pair<int, int> ii;
const int N = 2e5+5;
const int M = 350;
const int mod = 1e9+7;
const int INF = 1e18;
using cd = complex<double>;
const long double PI = acos(-1);
int power(int a,int b) {ll x = 1;if (a >= mod) a%=mod; while (b) {if (b & 1) x = x*a % mod;a = a*a % mod;b>>=1;}return x;}
int n;
int d[N],x[N],dp[N],sum[N][M+50];
void solve()
{
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]>=M)
{
for (int j=1;j<=x[i];j++)
{
if (i + d[i] * j > n) break;
dp[i] = (dp[i] + dp[i + d[i]*j])%mod;
}
}
if (d[i]<M && 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)%mod;
}
for (int j=1;j<=M;j++) sum[i][j] = (sum[i+j][j] + dp[i])%mod;
}
cout<<dp[1];
}
signed main()
{
bruh
//freopen("input.inp","r",stdin);
//freopen("output.inp","w",stdout);
int t = 1;
//cin>>t;
while (t--)
{
solve();
cout<<"\n";
}
}
