#include <bits/stdc++.h>
using namespace std;
using lint = long long;
const int INF = 1e9;
const lint LINF = 1e18;
const lint MOD = 1e9 + 7;
const double EPS = 1e-10;
int main() {
  int n, h;
  cin >> n >> h;
  vector<pair<lint, lint>> a(n);
  for (int i = (int)(0); i < (int)(n); i++) {
    cin >> a[i].first >> a[i].second;
  }
  sort(a.begin(), a.end());
  reverse(a.begin(), a.end());
  int s = a[0].first;
  vector<lint> sub(0);
  for (int i = 0; i < a.size(); i++) {
    if (s < a[i].second) {
      sub.push_back(a[i].second);
    } else {
      continue;
    }
  }
  sort(sub.begin(), sub.end());
  reverse(sub.begin(), sub.end());
  int times = 0;
  while (h > 0) {
    if (sub.size() > 0) {
      h -= sub.front();
      sub.erase(sub.begin());
      times++;
    } else {
      break;
    }
  }
  times += (h + s - 1) / s;
  cout << times << endl;
  return 0;
}
