#include <iostream>

#include <cstdlib>

#include <cstring>

#include <cstdio>

#include <cmath>

#include <algorithm>

#include <queue>

using namespace std;

const int MaxN = 150000 + 5;

int n, Ans, Time;

struct ES

{

	int Ct, DL;

} E[MaxN];

bool Cmp(ES e1, ES e2)

{

	return e1.DL < e2.DL;

}

priority_queue<int> Q;

int main()

{

	scanf("%d", &n);

	for (int i = 1; i <= n; ++i) scanf("%d%d", &E[i].Ct, &E[i].DL);

	sort(E + 1, E + n + 1, Cmp);

	Time = 0; Ans = 0;

	while (!Q.empty()) Q.pop();

	for (int i = 1; i <= n; ++i)

	{

		if (Time + E[i].Ct <= E[i].DL)

		{

			Time += E[i].Ct;

			Q.push(E[i].Ct);

			++Ans;

		}

		else

		{

			if (Q.empty()) continue;

			if (E[i].Ct < Q.top())

			{

				Time -= Q.top();

				Q.pop();

				Time += E[i].Ct;

				Q.push(E[i].Ct);

			}

		}

	}

	printf("%d\n", Ans);

	return 0;

}