using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var n = NN;
        var map = NArr(n);
        WriteLine(Blocks(n, map));
    }
    static int Blocks(int n, int[][] map)
    {
        Array.Sort(map, (l, r) => (l[0] + l[1]).CompareTo(r[0] + r[1]));
        var dp = new long[n + 1][];
        for (var i = 0; i < dp.Length; ++i) dp[i] = Enumerable.Repeat(long.MaxValue / 2, n + 1).ToArray();
        dp[0][0] = 0;
        for (var i = 0; i < n; ++i)
        {
            for (var j = 0; j < n; ++j)
            {
                dp[i + 1][j] = Math.Min(dp[i + 1][j], dp[i][j]);
                if (dp[i][j] <= map[i][1]) dp[i + 1][j + 1] = Math.Min(dp[i + 1][j + 1], dp[i][j] + map[i][0]);
            }
        }
        var ans = 0;
        for (var i = 0; i <= n; ++i) if (dp[n][i] < long.MaxValue / 2) ans = i;
        return ans;
    }
}