// 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
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