#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long INF = 2 * 1e18;
const int inf = 1e9 + 7;
int main(void) {
  cin.tie(0);
  ios::sync_with_stdio(false);
  int N, H;
  cin >> N >> H;
  int amax = 0;
  vector<int> a(N), b(N);
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    amax = max(amax, a[i]);
  }
  sort((a).begin(), (a).end());
  sort((b).begin(), (b).end());
  int ans = 0;
  for (int i = N - 1; i >= 0; i--) {
    if (b[i] >= amax) {
      H -= b[i];
      ans++;
    }
    if (H <= 0) break;
  }
  if (H) {
    ans += (H + amax - 1) / amax;
  }
  cout << ans << endl;
}
