#include <bits/stdc++.h>
using namespace std;
template <class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
int main() {
  int N, H;
  cin >> N >> H;
  int maxHuruAtk = 0;
  vector<int> nageAtks(N);
  for (int i = 0, i_len = (N); i < i_len; ++i) {
    int a, b;
    cin >> a >> b;
    chmax(maxHuruAtk, a);
    nageAtks[i] = b;
  }
  sort((nageAtks).begin(), (nageAtks).end());
  int damage = 0;
  int count = 0;
  for (int i = 0, i_len = (N); i < i_len; ++i) {
    if (nageAtks[i] <= maxHuruAtk) continue;
    damage += nageAtks[i];
    count++;
    if (damage >= H) break;
  }
  if (damage < H) {
    auto d = (double)(H - damage) / maxHuruAtk;
    auto ac = ceil(d);
    count += ac;
  }
  cout << count << endl;
  return 0;
}
