#include <bits/stdc++.h>
#include <stdio.h>
using namespace std;

const int N = 1e5 + 10;
int n, ans;
long long h, sum;

struct get {
	long long a, b;
} A[N];

priority_queue <long long, vector <long long>, less <long long> > pq;

void read() {
	
	scanf("%d%lld", &n, &h);
	sum = h;
	for(int i = 1; i <= n; i++)
		scanf("%lld%lld", &A[i].a, &A[i].b);
}

void work() {
	
	for(int i = 1; i <= n; i++) {
		pq.push(A[i].a);
		sum -= A[i].a;
		if(sum <= 0) {
			while(!pq.empty() && sum <= 0) {
				sum += pq.top();
				pq.pop();
				ans++;
			}
		}
		sum += A[i].b;
	}
	
	printf("%d\n", ans);
}

int main() {
	
	read();
	work();
	return 0;
}