#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<pair<long long, long long>> p(n);
  for (long long i = 0; i < n; i++) {
    cin >> p[i].first >> p[i].second;
  }
  sort(p.begin(), p.end());
  vector<long long> bx(n - 1);
  for (long long i = 0; i < n - 1; i++) bx[i] = p[i].second;
  sort(bx.begin(), bx.end(), greater<long long>());
  long long amax = p[n - 1].first;
  long long cnt = 0;
  long long b = p[n - 1].second;
  if (b >= h) {
    cout << 1 << endl;
    return 0;
  }
  for (long long i = 0; i < n - 1; i++) {
    if (bx[i] >= amax) {
      h -= bx[i];
      cnt++;
      if (h <= 0) {
        cout << cnt << endl;
        return 0;
      }
    }
  }
  while (h > b) {
    h -= amax;
    cnt++;
  }
  if (h > 0 && h <= b)
    cout << cnt + 1 << endl;
  else
    cout << cnt << endl;
}
