#include <bits/stdc++.h>
using namespace std;
bool greaterOrdered(pair<long long, long long> pre,
                    pair<long long, long long> post) {
  if (pre.second > post.second)
    return true;
  else
    return false;
}
int main() {
  long long N, H;
  cin >> N >> H;
  long long hp = H;
  long long maxAttackPoint = 0;
  long long cnt = 0LL;
  vector<pair<long long, long long> > vec;
  for (long long i = 0LL; i < N; ++i) {
    long long A, B;
    cin >> A >> B;
    vec.push_back(pair<long long, long long>(A, B));
    maxAttackPoint = max(maxAttackPoint, A);
  }
  sort(vec.begin(), vec.end(), greaterOrdered);
  for (int i = 0; i < vec.size(); ++i) {
    if (hp <= 0) {
      cout << cnt << endl;
      return 0;
    }
    if (maxAttackPoint < vec[i].second) {
      hp -= vec[i].second;
      cnt++;
    } else {
      cnt += (hp % maxAttackPoint == 0) ? hp / maxAttackPoint
                                        : hp / maxAttackPoint + 1;
      cout << cnt << endl;
      return 0;
    }
  }
  if (hp <= 0) {
    cout << cnt << endl;
    return 0;
  }
  cnt += (hp % maxAttackPoint == 0) ? hp / maxAttackPoint
                                    : hp / maxAttackPoint + 1;
  cout << cnt << endl;
  return 0;
}
