#include "bits/stdc++.h"
using namespace std;
typedef long long LL;
int main() {
	int N, H;
	cin >> N >> H;
	vector<int> v;
	int max_a = 0;
	for (int i = 0; i < N; i++) {
		int a, b;
		cin >> a >> b;
		max_a = max(max_a, a);
		v.push_back(b);
	}
	sort(v.rbegin(), v.rend());
	int ans = 0;
	for (int i = 0; i < N; i++) {
		if (v[i] > max_a) H -= v[i], ans++;
		if (H <= 0) break;
	}
	if (H > 0) ans += (H + max_a - 1) / max_a;
	cout << ans << endl;
}