#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#define lol(i,n) for(int i=0;i<n;i++)
#define mod 1000000007
typedef long long ll;
using namespace std;
int n,h,a[100010],b[100010];
int main(){
	cin>>n>>h;
	int maxi=-1;
	lol(i,n){
		cin>>a[i]>>b[i];
		maxi=max(maxi,a[i]);
	}
	sort(b,b+n);
	int k=0;
	for(int i=n-1;i>=0;i--){
		if(b[i]<maxi)break;
		h-=b[i];
		k++;
		if(h<=0)break;
	}
	if(h>0){
		k+=(h+maxi-1)/maxi;
	}
	cout<<k<<endl;
	return 0;
}
