#include <iostream>
#include <algorithm>
using namespace std;

pair<long long, long long> p[1009];
long long d[1009][1009], inf = 1e18;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n; cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> p[i].second >> p[i].first;
        p[i].first += p[i].second;
    }
    sort(p + 1, p + n + 1);
    for (int i = 1; i <= n; i++)
        d[0][i] = inf;
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j <= n; j++) {
            d[i][j] = d[i - 1][j];
            if (j && d[i - 1][j - 1] + p[i].second <= p[i].first) d[i][j] = min(d[i][j], d[i - 1][j - 1] + p[i].second);
        }
    }
    int ans = 0;
    for (int i = n; i >= 1; i--)
        if (d[n][i] != inf) {
            ans = i;
            break;
        }
    cout << ans << '\n';
    return 0;
}