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

int main()
{
	ll N, H;
	cin >> N >> H;
	ll ma = 0;
	priority_queue<ll> pq;
	for (int i = 0; i < N; i++) {
		ll a, b;
		cin >> a >> b;
		ma = max(ma, a);
		pq.push(b);
	}
	ll res = 0;
	while (H > 0) {
		if (pq.empty() || pq.top() < ma) {
			ll t = (H + ma - 1) / ma;
			res += t;
			break;
			H = t * ma;
		}
		else {
			H -= pq.top(); pq.pop();
			res++;
		}
	}
	cout << res << endl;
	return 0;
}
