#include <bits/stdc++.h>

using namespace std;

int main(){
	int n,h;
	cin >> n >> h;
	vector<int> a(n);
	vector<int> b(n);
	for(int i=0;i<n;i++){
		cin >> a[i] >> b[i];	
	}
	sort(a.begin(),a.end());
	sort(b.begin(),b.end());
	int ans=0;
	int damage = 0;
	int i=n-1;
	while(damage < h){
		if(i >= 0 && a[n-1] < b[i]){
			damage += b[i];
			i--;
			ans++;
		} else {
			ans += (h-damage)/a[n-1] + ((h-damage)%a[n-1] != 0);
			break;
		}
	}
	cout << ans << endl;
	return 0;
}