#include <bits/stdc++.h>
using namespace std;
const long long INF = 1LL << 58;
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T &a, const T &b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T>
void remove(T &vector, unsigned int index) {
  vector.erase(vector.begin() + index);
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  long long N, H;
  cin >> N >> H;
  vector<long long> a(N), b(N);
  for (int i = 0; i < (int)(N); i++) cin >> a[i] >> b[i];
  long long ma = *max_element(a.begin(), a.end());
  int cnt = 0;
  for (int i = 0; i < (int)(N); i++) {
    if (b[i] > ma) {
      H -= b[i];
      cnt++;
    }
    if (H <= 0) break;
  }
  if (H <= 0) {
    cout << cnt << endl;
    return 0;
  }
  while (true) {
    H -= ma;
    cnt++;
    if (H <= 0) break;
  }
  cout << cnt << endl;
  return 0;
}
