#include <bits/stdc++.h>
using namespace std;
int max(int* array, int n) {
  int max = 0;
  for (int i = 0; i < n; i++)
    if (array[i] > max) max = array[i];
  return max;
}
int main() {
  int N, H;
  cin >> N >> H;
  int a[N], b[N];
  for (int i = 0; i < N; i++) cin >> a[i] >> b[i];
  int a_max = max(a, N);
  sort(b, b + N, greater<int>());
  int damage = 0, count = 0;
  for (int i = 0; i < N; i++) {
    if (damage < H) {
      if (b[i] > a_max) {
        damage += b[i];
        count++;
      } else
        break;
    } else {
      cout << count << endl;
      return 0;
    }
  }
  if ((H - damage) % a_max == 0)
    count += (H - damage) / a_max;
  else
    count += (H - damage) / a_max + 1;
  cout << count << endl;
  return 0;
}
