#include <bits/stdc++.h>
using namespace std;
int main() {
  long n, h;
  cin >> n >> h;
  vector<long> b(n);
  long a = 0;
  for (long i = 0; i < n; i++) {
    long an;
    cin >> an >> b[i];
    if (an > a) a = an;
  }
  sort(b.begin(), b.end(), greater<long>());
  long a_num = h / a;
  a_num += h % a == 0 ? 0 : 1;
  long b_sum = 0;
  long b_num = 0;
  for (long i = 0; i < n; i++) {
    if (b_sum >= h) break;
    if (a >= b[i]) break;
    b_num++;
    b_sum += b[i];
    a_num = (h - b_sum) / a;
    if (h > b_sum) a_num += (h - b_sum) % a == 0 ? 0 : 1;
  }
  printf("%ld", a_num + b_num);
  return 0;
}
