#include <bits/stdc++.h>
using namespace std;
int main() {
  double n, h;
  cin >> n >> h;
  int a[100000];
  int b[100000];
  int m = 0;
  vector<int> srow;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    if (m < a[i]) m = a[i];
  }
  for (int i = 0; i < n; i++) {
    if (m < b[i]) srow.push_back(b[i]);
  }
  sort(srow.begin(), srow.end());
  int count = 0;
  double sum = 0;
  while (sum < h) {
    if (count < srow.size()) {
      sum += srow[count];
      count++;
    } else {
      int tmp = (int)(ceil((h - sum) / m));
      count += tmp;
      sum += tmp * m;
    }
  }
  cout << count << endl;
}
