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

int main(){
	int N, H, ans = 0, dam = 0;
	cin >> N >> H;
	int a[N], b[N];
	for(int i = 0; i < N; i++)
		cin >> a[i] >> b[i];
	sort(b,b+N);
	int amax = 0;
	for(int i = 0; i < N; i++)
		amax = max(amax,a[i]);
	for(int i = N-1; i >= 0; i--){
		if(b[i] < amax || dam >= H)
			break;
		dam += b[i];
		ans++;
	}
	while(dam < H){
		dam += amax;
		ans++;
	}
	cout << ans << endl;
	return 0;
}