#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define FORR2(x,y,arr) for(auto& [x,y]:arr)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
template<class T> bool chmax(T &a, const T &b) { if(a<b){a=b;return 1;}return 0;}
template<class T> bool chmin(T &a, const T &b) { if(a>b){a=b;return 1;}return 0;}
//-------------------------------------------------------

int N;
ll W[1010],S[1010];
pair<int,int> P[1010];

ll dp[1010];

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	FOR(i,N) {
		cin>>W[i]>>S[i];
		P[i]={W[i]+S[i],i};
	}
	sort(P,P+N);
	
	FOR(x,N+1) dp[x]=1LL<<60;
	dp[0]=0;
	int ma=0;
	FOR(i,N) {
		x=P[i].second;
		for(j=N-1;j>=0;j--) {
			if(dp[j]<=S[x]) {
				dp[j+1]=min(dp[j+1],dp[j]+W[x]);
			}
		}
	}
	FOR(j,N+1) if(dp[j]<1LL<<60) ma=j;
	cout<<ma<<endl;
	
	
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}