#include <iostream>
#include <algorithm>

int n;
long long h, a[100005], b[100005];
int main() {
	std::cin >> n >> h;
	for (int i = 0; i < n; ++i)
		std::cin >> a[i] >> b[i];
	std::sort(a, a + n, std::greater<long long>());
	std::sort(b, b + n, std::greater<long long>());

	long long ans = 0;
	for (int i = 0; i < n&&h>0; ++i)
		if (b[i] > a[0])
			++ans, h -= b[i];
	if (h > 0)
		ans += (h + a[0] - 1) / a[0];
	std::cout << ans << std::endl;
	return 0;
}
