#include <algorithm>
#include <cstdio>

using namespace std;

int a[100000], b[100000], n, h;

int main(void) {
	scanf("%d %d", &n, &h);
	for(int i= 0; i < n; i++) scanf("%d %d", a + i, b + i);
	sort(a, a + n);
	sort(b, b + n);
	
	int largest = a[n - 1];
	int ans = 0;
	for(int i = n - 1; i >= 0; i--) {
		if(b[i] <= largest) break;
		h -= b[i];
		ans++;
		if(h <= 0) break;
	}
	
	if(h > 0) ans += (h + largest - 1) / largest;
	printf("%d\n", ans);
	return 0;
}