#include <iostream>
#include <set>
#include <algorithm>

using namespace std;

#define b first
#define a second

const int N = int(2 * 1e5 + 10);

pair<long long, long long> v[N];
multiset<long long> s;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);

    int n;
    cin >> n;

    for (int i = 0; i < n; ++i) {
        cin >> v[i].a >> v[i].b;
        v[i].b += v[i].a;
    }

    sort(v, v + n);

    int res = -1;

    long long cnt = 0;

    for (int i = 0; i < n; ++i)
    {
        s.insert(v[i].a);
        cnt += v[i].a;

        while (res != -1 && res <= s.size()) {
            cnt -= *(s.begin());
            s.erase(s.begin());
        }

        while (cnt >= v[i].b)
        {
            res = s.size();
            cnt -= *(s.begin());
            s.erase(s.begin());
        }
    }

    cout << res << endl;

    return 0;
}