#include <bits/stdc++.h>
using namespace std;
template <typename T>
void DEBUG(T e) {
  if (true == false) return;
  std::cout << e << " ";
}
template <typename T>
void DEBUG(const std::vector<T>& v) {
  if (true == false) return;
  for (const auto& e : v) {
    std::cout << e << " ";
  }
  std::cout << std::endl;
}
template <typename T>
void DEBUG(const std::vector<std::vector<T> >& vv) {
  if (true == false) return;
  for (const auto& v : vv) {
    DEBUG(v);
  }
}
template <class T, class... Ts>
void DEBUG(T d, Ts... e) {
  if (true == false) return;
  DEBUG(d);
  DEBUG(e...);
}
template <class T>
void corner(bool flg, T hoge) {
  if (flg) {
    cout << hoge << endl;
    exit(0);
  }
}
template <typename T1, typename T2>
inline bool chmax(T1& a, T2 b) {
  return a < b && (a = b, true);
}
template <typename T1, typename T2>
inline bool chmin(T1& a, T2 b) {
  return a > b && (a = b, true);
}
void solve(void) {
  long long N, H;
  cin >> N;
  cin >> H;
  vector<long long> A(N, 0);
  vector<long long> B(N, 0);
  long long index = -1;
  long long MAX = 0;
  for (long long i = 0; i < N; i++) {
    cin >> A[i] >> B[i];
    if (chmax(MAX, A[i])) {
      index = i;
    }
  }
  long long ANS = 0;
  for (long long i = 0; i < N; i++) {
    if (MAX < B[i] && i != index) {
      H -= B[i];
      ANS++;
    }
    if (H <= 0) break;
  }
  if (H > 0) {
    H -= B[index];
    ANS++;
    ANS += H / A[index] + (long long)(H % A[index] > 0);
  }
  cout << ANS << endl;
  return;
}
int32_t main(int32_t argc, const char* argv[]) {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);
  std::cout << std::fixed;
  std::cout << std::setprecision(9);
  solve();
  return 0;
}
