#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<ll, ll> pp;
typedef vector<pp> vp;
typedef map<pp, ll> ipi;
typedef map<pp, char> ipc;
typedef map<ll, ll> ii;
typedef set<ll> sl;
typedef multiset<ll> msl;
typedef map<char, ll> ci;
typedef set<pair<ll, ll>> sp;
const ll mod = 1e9 + 7;
const ll N = 1e6 + 1;
void solve() {
  ll n, hp;
  cin >> n >> hp;
  multiset<pp> m, m2;
  for (int i = 0; i < n; i++) {
    ll a, b;
    cin >> a >> b;
    m.insert({a, b});
  }
  pp atk = *--m.end();
  ll ans = 0;
  m.erase(--m.end());
  while (!m.empty()) {
    if ((*--m.end()).second > atk.first) {
      hp -= (*--m.end()).second;
      ans++;
    }
    m.erase(--m.end());
  }
  if (atk.second >= atk.first) {
    hp -= atk.second;
    ans++;
  }
  if (hp > 0) ans += ceil(double(hp) / double(atk.first));
  cout << ans << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ll t;
  t = 1;
  while (t--) {
    solve();
  }
  return 0;
}
