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