#include <bits/stdc++.h>

 using namespace std;

 const int maxn=+;

 int n;

 struct node{

     int t1,t2;

     node(int t1=,int t2=):t1(t1),t2(t2){}

     bool operator < (const node &a) const { return t2<a.t2; }

 }a[maxn];

 inline void solve(){

     priority_queue <int> q;

     int now=,ans=;

     for(int i=;i<=n;i++){

         if(now+a[i].t1<=a[i].t2) q.push(a[i].t1),now+=a[i].t1,ans++;

         else if(a[i].t1<=q.top()&&now-q.top()+a[i].t1<=a[i].t2){

             now+=a[i].t1-q.top();

             q.pop(); q.push(a[i].t1);

         }

     }

     printf("%d\n",ans);

 }

 inline void init(){

     scanf("%d",&n);

     for(int i=;i<=n;i++) scanf("%d%d",&a[i].t1,&a[i].t2);

     sort(a+,a++n);

 }

 int main(){

     init();

     solve();

     return ;

 }