#include <bits/stdc++.h>
using namespace std;
int a[10001] = {};
int b[10001] = {};
int main() {
  int n, h;
  cin >> n >> h;
  for (int i = 0; i < n; ++i) cin >> a[i] >> b[i];
  sort(a, a + n);
  sort(b, b + n);
  int t = 0;
  int c = 0;
  int k = n - 1;
  while (t < h) {
    if (b[k] > a[n - 1] && (k >= 0)) {
      t += b[k];
      k--;
      c++;
    } else {
      c += ((h - t) / a[n - 1]);
      if ((h - t) % a[n - 1] > 0) c++;
      t = h + 1;
    }
  }
  cout << c << endl;
  return 0;
}
