#include <bits/stdc++.h>
using namespace std;
using pii = pair<long long, long long>;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
const long long MOD = 1000000007;
const long long INF = 1LL << 30;
const double EPS = 1e-10;
long long N, H;
pii ps[100010];
signed main() {
  cin.tie(0);
  ios_base::sync_with_stdio(false);
  cout << fixed << setprecision(10);
  cin >> N >> H;
  for (long long i = 0; i < (N); ++i) {
    long long a, b;
    cin >> a >> b;
    ps[i] = make_pair(a, b);
  }
  sort(ps, ps + N);
  long long ans = 0;
  for (long long i = (N - 2); i >= 0; --i)
    if (H > 0 && ps[i].second > ps[N - 1].first) {
      ans++;
      H -= ps[i].second;
    }
  if (H > 0) {
    ans++;
    H -= ps[N - 1].second;
    if (H > 0) ans += (H + ps[N - 1].first - 1) / ps[N - 1].first;
  }
  cout << ans << endl;
  return 0;
}
