#include<bits/stdc++.h>
using namespace std;
int main()
{
	int a[10010],b[10010];
	int n,hp;
	int mx=0;
	int ans=0;
	queue<int>q;
	cin>>n>>hp;
	for(int i=0;i<n;i++)
	{
		cin>>a[i]>>b[i];
		if(a[i]>mx)mx=a[i];
	}
	sort(b,b+n);
	reverse(b,b+n);  
	for(int i=0;i<n;i++)
	{
		if(b[i]>=mx)q.push(b[i]);
	}
	while(hp>0){
		while(!qempty()){
			ans++;
			hp-=q.front();
			q.pop();
			if(hp<=0){
				cout<<ans<<endl;
				return 0;
			}
			}
		ans+=(hp+mx-1)/mx;
		hp=0;
	}
	cout<<ans<<endl;
	return 0;
}