#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() {
  long long N, H;
  cin >> N >> H;
  vector<long long> nageAtks(N), a(N);
  for (int i = 0, i_len = (N); i < i_len; ++i) cin >> a[i] >> nageAtks[i];
  long long maxHuruAtk = *max_element((a).begin(), (a).end());
  long long count = 0;
  sort((nageAtks).begin(), (nageAtks).end());
  for (int i = 0, i_len = (N); i < i_len; ++i) {
    if (nageAtks[i] > maxHuruAtk) {
      H -= nageAtks[i];
      count++;
      if (H <= 0) break;
    }
  }
  if (H > 0) {
    count += (H + maxHuruAtk - 1) / maxHuruAtk;
  }
  cout << count << endl;
  return 0;
}
