#include <bits/stdc++.h>
using namespace std;
bool comp(pair<int, int> &a, pair<int, int> &b) {
  if (a.first == b.first) {
    return a.second < b.second;
  }
  return a.first > b.first;
}
int main() {
  int n, h;
  cin >> n >> h;
  vector<pair<int, int>> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i].first >> v[i].second;
  }
  sort(v.begin(), v.end(), comp);
  int ans = 0;
  for (int i = 1; i < n; i++) {
    if (h > 0 && v[i].second >= v[0].first) {
      h -= v[i].second;
      ans++;
    }
  }
  if (h > 0 && v[0].second > v[0].first) {
    h -= v[0].second;
    ans++;
  }
  if (h > 0) {
    ans += (h + v[0].first - 1) / v[0].first;
  }
  cout << ans << '\n';
  return 0;
}
