#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
template <class T>
using V = vector<T>;
using Graph = vector<vector<int>>;
using P = pair<long long, long long>;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
int main() {
  int n;
  long long h;
  cin >> n >> h;
  V<P> p(n);
  for (int i = 0; i < n; i++) {
    long long a, b;
    cin >> a >> b;
    p[i] = make_pair(a, b);
  }
  sort((p).begin(), (p).end());
  long long u = p[n - 1].first;
  long long cnt = 0;
  long long ans = 0;
  for (int i = 0; i < n - 1; i++) {
    if (p[i].second > u) {
      ans++;
      cnt += p[i].second;
      if (cnt >= h) break;
    }
  }
  if (cnt < h) {
    long long v = p[n - 1].second;
    cnt += v;
    ans++;
    while (cnt < h) {
      ans++;
      cnt += u;
    }
  }
  cout << ans << endl;
}
