#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using Graph = vector<vector<int>>;
const ll MOD = 1000000007;
const ll INF = 9999999999;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline T powerM(T a, T b) {
  if (b == 0) return 1;
  T tmp = powerM(a, b / 2);
  if (b % 2 == 0)
    return tmp * tmp % MOD;
  else
    return tmp * tmp % MOD * a % MOD;
}
int main() {
  int n, h;
  cin >> n >> h;
  vector<ll> attack(n), throws(n);
  for (int i = 0; i < (int)(n); i++) cin >> attack.at(i) >> throws.at(i);
  ll attackmax = 0;
  for (int i = 0; i < (int)(n); i++) chmax(attackmax, attack.at(i));
  vector<ll> throwThanAttackmax;
  for (int i = 0; i < (int)(n); i++)
    if (throws.at(i) > attackmax) throwThanAttackmax.push_back(throws.at(i));
  sort(throwThanAttackmax.begin(), throwThanAttackmax.end());
  reverse(throwThanAttackmax.begin(), throwThanAttackmax.end());
  int ans = 0;
  for (int i = 0; i < throwThanAttackmax.size(); i++) {
    h -= throwThanAttackmax.at(i);
    ans++;
    if (h <= 0) break;
  }
  ans += (h + attackmax - 1) / attackmax;
  cout << ans << endl;
}
