#include <bits/stdc++.h>
using namespace std;
int N, H;
int main() {
  int i, x = 0;
  int a, max;
  cin >> N >> H;
  vector<int> b(N);
  for (i = 0; i < N; i++) {
    cin >> a >> b[i];
    max = (((a) > (max)) ? (a) : (max));
  }
  sort(b.begin(), b.end());
  reverse(b.begin(), b.end());
  for (i = 0; i < N; i++) {
    if (max < b[i]) {
      H -= b[i];
      x++;
    } else
      break;
  }
  while (H > 0) {
    H -= max;
    x++;
  }
  cout << x << endl;
  return 0;
}
