#include<stdio.h>
#include<algorithm>
#include<functional>
using namespace std;
int main()
{
	int N, H, count = 0;
	long long a[100000], b[100000], max = 0;
	scanf("%d%d", &N, &H);
	for (int i = 0; i < N; i++) {
		scanf("%lld%lld", &a[i], &b[i]);
		if (a[i] > max) {
			max = a[i];
		}
	}
	sort(b, b + N, greater<int>());
	int j = 0;
	while (H > 0) {
		if (max >= b[j]) {
			H -= max;
		}
		else {
			H -= b[j];
			j++;
		}
		count++;
	}
	printf("%d", count);
	return 0;
}