// iostream is too mainstream
#include <cstdio>
// bitch please
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <string>
#include <queue>
#include <stack>
#include <algorithm>
#include <iomanip>
#define dibs reserve
#define OVER9000 1234567890
#define patkan 9
#define tisic 47
#define soclose 10e-7
#define ALL_THE(CAKE,LIE) for(auto LIE =CAKE.begin(); LIE != CAKE.end(); LIE++)
#define chocolate win
#define ff first
#define ss second
#define abs(x) ((x < 0)?-(x):(x))
// mylittlepony
using namespace std;
	
int main() {
    cin.sync_with_stdio(0);
    int N;
    cin >> N;
    int ans =0;
    long long t,d, dt =0;
    priority_queue<int> q;
    
    for(int i =0; i < N; i++) {
    	cin >> t >> d;
    	q.push(d);
    	dt +=d;
    	while(dt > t) {
    		dt -=q.top();
    		ans++;
    		q.pop();}
    	}
    
    cout << ans << "\n";
    return 0;}
        
// look at my code
// my code is amazing