#include <bits/stdc++.h>
using namespace std;

const int Nmax = 100010;
int N, H;
int a[Nmax], b[Nmax];

int main() {
	cin >> N >> H;
	for (int i = 0; i < N; i++) {
		cin >> a[i] >> b[i];
	}
	sort(a, a + N);
	sort(b, b + N);
	int Amax = a[N - 1];
	int ans = 0;
	int i = N - 1;
	while (H > 0) {
		if (b[i] > Amax) {
			H -= b[i];
			i--;
			ans++;
		}
		else {
			if (H%Amax == 0) ans += H / Amax;
			else ans += H / Amax + 1;
			break;
		}
	}

	cout << ans << endl;
}