#include <cstdio>
#include <vector>
#include <algorithm>
#include <iostream>
#include <cstring>
#include "optimization.h"
#include <stack>
#include <string>
#include <stdlib.h>
#include <stdio.h>
#include <vector>
#include <map>
#include <unordered_map>
#include <list>
#include <set>
#include <bits/stdc++.h>


struct vasyna_korobka{
    int ves;
    int tyasheloves;
};

bool proverka(vasyna_korobka& a, vasyna_korobka& b){
    return (a.ves + a.tyasheloves < b.ves + b.tyasheloves);
}

int main(){


 //   freopen("text.in", "r", stdin);

    int n;
    n = readInt();
    std::vector<vasyna_korobka> uborka(n);
    for (int i = 0; i < n; ++i){
        uborka[i].ves = readInt();
        uborka[i].tyasheloves = readInt();
    }
    std::sort(uborka.begin(), uborka.end(), proverka);


    std::priority_queue<int> take;
    int cnt = 1;
    int all = uborka[0].ves;
    int samaya_tyasholaya = uborka[0].ves;
    take.push(all);
    for (int i = 1; i < n; ++i){
        if (all <= uborka[i].tyasheloves){
            cnt++;
            all += uborka[i].ves;
            take.push(uborka[i].ves);
            samaya_tyasholaya = take.top();
        }
        else
        if (samaya_tyasholaya >= uborka[i].ves){
            all = all + uborka[i].ves - samaya_tyasholaya;
            take.pop();
            take.push(uborka[i].ves);
            samaya_tyasholaya = take.top();
        }
    }

    writeInt(cnt);
}