#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
	int N, H;
	cin >> N >> H;
	int AMAX = 0;
	vector<int> B(N);
	for (int i = 0; i < N; i++) {
		int a;
		cin >> a >> B[i];
		AMAX = max(AMAX, a);
	}
	sort(B.begin(), B.end(), greater<int>());
	int ans = 0;
	for (int i = 0; i < N; i++) {
		H -= max(AMAX, B[i]);
		ans++;
		if (H <= 0) break;
	}
	cout << ans + max(0, (H + AMAX - 1) / AMAX) << endl;
}