#include <iostream>
#include <utility>
#include <algorithm>
using namespace std;

int main() {
  int n, h;
  cin >> n >> h;
  vector<int> a(n), b(n);
  vector<pair<int, int>> s;
  int i;
  for (i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    s.push_back(make_pair(a[i], 1));
    s.push_back(make_pair(b[i], 0));
  }
  sort(s.begin(), s.end());
  int result = 0;
  for (i = s.size() - 1; i >= 0 && h > 0; i--) {
    if (s[i].second) {
      result += (h + s[i].first - 1) / s[i].first;
      h = 0;
    } else {
      result++;
      h -= s[i].first;
    }
  }
  cout << result << endl;
  return 0;
}
