#include <iostream>
#include <algorithm>
using namespace std;

int main()
{
	long long int N, H, a[100000], b[100000], ans = 0;

	cin >> N >> H;

	for (int i = 0; i < N; i++) {
		cin >> a[i] >> b[i];
	}

	sort(a, a + N);
	sort(b, b + N);

	reverse(a, a + N);
	reverse(b, b + N);

	for (int i = 0; i < N; i++) {
		if (a[0] >= b[i]|| H <= 0)break;
		H -= b[i];
		ans++;
	}

	if (H > 0) {
		ans += H / a[0];
		if (H%a[0])ans++;
	}

	cout << ans;

	return 0;
}