#pragma GCC optimize("O1,O2,O3,Ofast,unroll-loops")
#include <bits/stdc++.h>
#include <string>
#include <iostream>
#include <cmath>
#include <numeric>
#include <stack>
#include <queue>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ld, ld> pd;
typedef vector<int> vi;
typedef vector<bool> vb;
typedef vector<vector<int>> vvi;
typedef vector<vector<pi>> vvpi;
typedef vector<ld> vd;
typedef vector<long long> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
#define FOR(i, a, b) for (ll i = a; i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i, a, b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i, a) for (int i = (a)-1; i >= 0; i--)
#define trav(a, x) for (auto &a : x)
#define uid(a, b) uniform_int_distribution<int>(a, b)(rng)
#define len(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define F first
#define nl endl
#define S second
#define lb lower_bound
#define ub upper_bound
#define aint(x) x.begin(), x.end()
#define raint(x) x.rbegin(), x.rend()
#define ins insert
const int M = 1e9+7;
void init(string name)
{
freopen((name + ".in").c_str(), "r", stdin);
freopen((name + ".out").c_str(), "w", stdout);
}
void fastIO()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
}
int add(int a,int b){
a += b;
if(a<0)a+=M;
return a%M;
}
void solve()
{
int N;cin >> N;
vi d(N), t(N);
vi dp(N+4,0);
FOR(i,0,N){
int a,b;cin >> a >> b;
d[i] = a;t[i] = b;
}
priority_queue<pi> pq;
int sum = 1,cnt = 1;
// dp[0] = 1;
FOR(i,0,N){
pq.push({-(i+t[i]),cnt});
cnt = add(cnt,dp[i]);
// cout << i << " " << pq.top().F << " | " << pq.top().S << " " << cnt << " ";
if(-pq.top().F == i){
cnt = add(cnt,-pq.top().S);
pq.pop();
}
// cout << cnt << endl;
dp[i+1] = add(cnt,dp[i+1]);
}
dp[0] = 1;
// FOR(i,0,N){
// cout << dp[i] << " ";
// }cout << endl;
int ans = 0;
FOR(i,0,N)ans = add(ans,dp[i]);
cout << ans << endl;
}
int main()
{
fastIO();
// init("test");
int t = 1;
// cin >> t;
while (t--)
solve();
return 0;
}
