#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll, ll>;
const ll INF = 9e18;
ll n, h, a[100001], b[100001];
signed main() {
  cin >> n >> h;
  ll max_a = 0, ret = 0;
  for (ll i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    max_a = max(max_a, a[i]);
  }
  sort(b, b + n);
  for (ll i = 0; i < n; i++) {
    if (b[i] > max_a) {
      h -= b[i];
      ret++;
    }
    if (h <= 0) break;
  }
  if (h > 0) ret += (h % max_a == 0) ? h / max_a : h / max_a + 1;
  cout << ret << endl;
  return 0;
}
