#include<bits/stdc++.h>
using namespace std;
int n,h,ans,mx;
int a[100005],b[100005];
bool cmp(int a,int b){
	return a>b;
}
int main(){
	cin>>n>>h;
	for(int i=0;i<n;i++){
		cin>>a[i]>>b[i];
		mx=max(mx,a[i]);
	}
	sort(b,b+n,cmp);
	for(int i=0;i<n;i++)
		if(h>0&&b[i]>mx){
			h-=b[i];
			ans++;
		}
	if(h>0)
		ans+=(h+mx-1)/mx;
	cout<<ans;
	return 0;
}