#include<cstdio>

 #include<queue>

 #include<algorithm>

 using namespace std;

 priority_queue<int,vector<int> >Heap;

 struct Point{int x,y;};

 bool cmp(const Point &a,const Point &b){return a.y<b.y;}

 int n,v,used,ans=;

 Point a[];

 int main()

 {

     scanf("%d",&n);

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

     sort(a+,a+n+,cmp);

     used=a[].x;Heap.push(a[].x);

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

       {

           if(used+a[i].x<=a[i].y)

             {

                 Heap.push(a[i].x);

                 used+=a[i].x;

                 ans++;

                 continue;

             }

           v=Heap.top();

           if(v>a[i].x)

             {

                 Heap.pop();

                 Heap.push(a[i].x);

                 used+=(a[i].x-v);

             }

       }

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

 }