#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  int a = 0, b[100000];
  for (int i = 0; i < n; i++) {
    int tmp;
    cin >> tmp >> b[i];
    a = max(a, tmp);
  }
  sort(b, b + n, greater<int>());
  int att = 0, thr = 0;
  while (h > 0) {
    if (thr == n || a > b[thr]) {
      att += ceil(h / (double)a);
      break;
    } else {
      h -= b[thr++];
      att++;
    }
  }
  cout << att << endl;
  return 0;
}
