#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>

using namespace std;

pair<int, int> box[100000];
int d[1000][1000];

bool q(pair<int, int> a, pair<int, int> b) {
    if (a.first + a.second == b.first + b.second)
        return a.first < b.first;
    return a.first + a.second < b.first + b.second;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin >> n;
    for (int i = 0; i < n; i++)
        cin >> box[i].first >> box[i].second;

    sort(box, box + n, q);
    priority_queue<int> used;
    int sum = 0;
    for (int i = 0; i < n; i++) {
        if (sum <= box[i].second) {
            used.push(box[i].first);
            sum += box[i].first;
        } else if (box[i].first < used.top()) {
            sum -= used.top();
            used.pop();
            used.push(box[i].first);
            sum += box[i].first;
        }
    }

    cout << used.size();
}