#include <bits/stdc++.h>
using namespace std;
constexpr int64_t mod = 1e9 + 7;
int main() {
  int n, h;
  cin >> n >> h;
  vector<int> a(n), b(n);
  for (int i = 0; i < n; ++i) {
    cin >> a[i] >> b[i];
  }
  int tmp = *max_element(a.begin(), a.end());
  int cnt = 0;
  for (int i = 0; i < n; ++i) {
    if (b[i] > tmp) {
      cnt++;
      h -= b[i];
    }
    if (h <= 0) {
      cout << cnt;
      return 0;
    }
  }
  cnt += h / tmp;
  if (h % tmp != 0) cnt++;
  cout << cnt;
}
