#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<int> w(N), s(N);
  for (int i = 0; i < N; i++){
    cin >> w[i] >> s[i];
  }
  vector<pair<int, int>> P(N);
  for (int i = 0; i < N; i++){
    P[i] = make_pair(w[i] + s[i], i);
  }
  sort(P.begin(), P.end());
  long long sum = 0;
  int cnt = 0;
  for (int i = 0; i < N; i++){
    if (sum <= s[P[i].second]){
      cnt++;
      sum += w[P[i].second];
    }
  }
  cout << cnt << endl;
}