#include<bits/stdc++.h>
#define int long long
using namespace std;
const int INF=1e18;
struct block{int w,s;};
void chmin(int&a,int b){if(a>b)a=b;}
block B[1100];
int dp[1100][1100];
signed main(){
  int N;cin>>N;
  for(int i=0;i<N;i++)cin>>B[i].w>>B[i].s;
  sort(B,B+N,[](block a,block b){return a.w+a.s<b.w+b.s;});
  fill(dp[0],dp[N+1],INF);
  dp[0][0]=0;
  for(int i=0;i<N;i++){
    for(int j=0;j<=N;j++)dp[i+1][j]=dp[i][j];
    for(int j=0;j<N;j++){
      if(dp[i][j]<=B[i].s)chmin(dp[i+1][j+1],dp[i][j]+B[i].w);
    }
  }
  for(int i=N;i>0;i--){
    if(dp[N][i]<=INF/2)return cout<<i<<endl,0;
  }
  cout<<0<<endl;
}