#include <bits/stdc++.h>
using namespace std;
const double EPS = 1e-10;
const int INF = 1e+9;
const double PI = acos(-1);
auto main() -> int {
  int n, h;
  cin >> n >> h;
  int a[100000], b[100000];
  for (int(i) = (0); (i) < (n); (i)++) {
    cin >> a[i] >> b[i];
  }
  int maxA = *max_element(a, a + n);
  sort(b, b + n);
  reverse(b, b + n);
  int count = 0;
  for (int(i) = (0); (i) < (n); (i)++) {
    if (b[i] <= maxA) {
      continue;
    }
    h -= b[i];
    ++count;
  }
  if (h > 0) {
    count += h / maxA;
    if (h % maxA != 0) {
      ++count;
    }
  }
  cout << count << endl;
  return 0;
}
