#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  vector<int> a(n), b(n);
  for (long long(i) = 0; (i) < (long long)(n); ++(i)) cin >> a[i] >> b[i];
  int kaisu = 0;
  int a_max = 0;
  for (long long(i) = 0; (i) < (long long)(n); ++(i)) {
    a_max = max(a_max, a[i]);
  }
  for (long long(i) = 0; (i) < (long long)(n); ++(i)) {
    if (a_max < b[i]) {
      h -= b[i];
      kaisu++;
    }
  }
  if (h % a_max == 0) {
    kaisu += h / a_max;
  } else {
    kaisu += h / a_max + 1;
  }
  cout << kaisu << endl;
  return 0;
}
