#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
const int INF = 1001001001;
const long long INFLL = LLONG_MAX / 3;
const double eps = (1e-9);
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll n, h;
  cin >> n >> h;
  vector<ll> a(n), b(n);
  for (ll i = 0; i < n; ++i) cin >> a[i] >> b[i];
  ll a_max = *std::max_element(a.begin(), a.end());
  sort((b).begin(), (b).end());
  ll ans = 0;
  while (h > 0) {
    if (b.back() > a_max) {
      h -= b.back();
      b.pop_back();
      ans++;
    } else {
      ans += (h + a_max - 1) / a_max;
      h = 0;
    }
  }
  cout << ans << endl;
  return 0;
}
