#include <bits/stdc++.h>
using namespace std;
int a[100000];
int b[100000];
int main() {
  int N, H;
  cin >> N >> H;
  int count = 0;
  for (int i = 0; i < N; i++) cin >> a[i] >> b[i];
  int amax = a[0];
  for (int i = 0; i < N - 1; i++) {
    amax = max(amax, a[i + 1]);
  }
  sort(b, b + N, greater<int>());
  for (int i = 0; i < N; i++) {
    if (amax > b[i]) break;
    count++;
    H -= b[i];
  }
  if (H % amax != 0) count++;
  count += H / amax;
  cout << count << endl;
  return 0;
}
