#include<stdio.h>
#include<algorithm>
int main() {
	int n, h, a, ans = 0, amax = 0, b[100000];
	scanf("%d %d", &n, &h);

	for (int i = 0; i < n; ++i) {
		scanf("%d %d", &a, &b[i]);
		amax = (amax < a ? a : amax);
	}
	std::sort(b, b+n); std::reverse(b, b+n);

	for (int i = 0; i < n && h > 0 && b[i] > amax; ++i) {
		h -= b[i];
		++ans;
	}
	if (h > 0) ans += (h + amax - 1) / amax;
	printf("%d\n", ans);
}