#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
constexpr ll INF = 9e18;
constexpr int inf = 1e9;
const double INFD = 1e100;
const ll mod = 1000000007;
const double PI = 3.1415926535897932384626433832795028841971;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
};
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
};
template <typename T>
inline string toString(const T& a) {
  ostringstream oss;
  oss << a;
  return oss.str();
};
int main() {
  ll N, H;
  cin >> N >> H;
  vector<ll> a(N), b(N);
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  ll swing_max = *max_element(a.begin(), a.end());
  sort(b.begin(), b.end(), greater<ll>());
  ll ans = 0;
  for (int i = 0; i < N; i++) {
    if (b[i] <= swing_max) break;
    H -= b[i];
    ans++;
  }
  ans += (H + swing_max - 1) / swing_max;
  cout << ans << endl;
  return 0;
}
