#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n;
  cin >> h;
  vector<int> a, b;
  int amax = -1;
  for (int i = 0; i < n; i++) {
    int a_, b_;
    cin >> a_;
    cin >> b_;
    a.push_back(a_);
    b.push_back(b_);
    amax = max(a_, amax);
  }
  int cnt = 0;
  for (int i = 0; i < b.size(); i++) {
    if (b[i] < amax) continue;
    cnt++;
    h -= b[i];
    if (h <= 0) {
      cout << cnt << endl;
      return 0;
    }
  }
  cnt += h / amax + !!(h % amax);
  cout << cnt << endl;
}
