using System;
using System.Collections;
using System.Collections.Generic;
 
class TEST{
	static void Main(){
		Sol mySol =new Sol();
		mySol.Solve();
	}
}

class Sol{
	public void Solve(){
		
		Array.Sort(P,(x,y)=>x.T>y.T?1:x.T<y.T?-1:0);
		
		HashSet<int>[] H=new HashSet<int>[2];
		H[0]=new HashSet<int>();
		H[0].Add(0);

		int now=0;
		int next=1;
		
		for(int i=0;i<N;i++){
			now=i%2;
			next=1-now;
			
			H[next]=new HashSet<int>();
			int maxx=0;
			foreach(int v in H[now]){
//Console.WriteLine("{0} {1}",i,v);
				if(v>=10002){
					maxx=Math.Max(maxx,v);
				}else{
					if(v<P[i].T){
						H[next].Add(v+P[i].V);
					}
					H[next].Add(v);
				}
				H[next].Add(maxx);
			}
		}
		
		int max=0;
		foreach(int k in H[next]){
			max=Math.Max(max,k);
		}
		Console.WriteLine(max);
		
	}
	int N;
	Pair[] P;
	public Sol(){
		N=ri();
		P=new Pair[N];
		for(int i=0;i<N;i++){
			P[i]=new Pair(ria());
		}
	}

	class Pair{
		public int V;
		public int T;
		public Pair(int[] in_){
			V=in_[0];T=in_[1];
		}
	}


	static String rs(){return Console.ReadLine();}
	static int ri(){return int.Parse(Console.ReadLine());}
	static long rl(){return long.Parse(Console.ReadLine());}
	static double rd(){return double.Parse(Console.ReadLine());}
	static String[] rsa(){return Console.ReadLine().Split(' ');}
	static int[] ria(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>int.Parse(e));}
	static long[] rla(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>long.Parse(e));}
	static double[] rda(){return Array.ConvertAll(Console.ReadLine().Split(' '),e=>double.Parse(e));}
}