#include <bits/stdc++.h>
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll I=1167167167167167167;
ll Q=1e9+7;
#define rep(i,a) for (ll i=0;i<a;i++)
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end());reverse(v.begin(),v.end());}
template<class T> void print_tate(vector<T> &v) {rep(i,v.size()) cout<<v[i]<<"\n";}
void yneos(bool a){if(a) cout<<"Yes"<<"\n"; else cout<<"No"<<"\n";}

//main関数だよーーー
int main() {
	int N;
	cin>>N;
	vector<pair<int,int>> p(N);
	rep(i,N){
		int H,P;
		cin>>P>>H;
		p[i]={H,P};
	}
	sort(p.begin(),p.end(),[](auto a,auto b){
		return a.first+a.second<b.first+b.second;
	});
	vector<vector<int>> dp(N+1,vector<int>(N+2,Q*2));
	dp[0][0]=0;
	rep(i,N) rep(j,i+1){
		if(dp[i][j]==Q*2) break;
		if(dp[i][j]<=p[i].first) chmin(dp[i+1][j+1],dp[i][j]+p[i].second);
		chmin(dp[i+1][j],dp[i][j]);
	}
	rep(i,N+1){
		if(dp[N][i+1]==Q*2){
			cout<<i<<"\n";
			return 0;
		}
		//cout<<dp[N][i+1]<<" "<<endl;
	}
}