#include <bits/stdc++.h>
using namespace std;
const long long dx[] = {1, -1, 0, 0};
const long long dy[] = {0, 0, -1, 1};
const double PI = 3.14159265358979323846;
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
template <typename T>
void printA(vector<T> &printArray, char between = ' ') {
  long long paSize = printArray.size();
  for (long long i = 0; i < paSize; i++) {
    cerr << printArray[i] << between;
  }
  if (between != '\n') {
    cerr << endl;
  }
}
long long N, H;
vector<long long> a, b;
signed main() {
  cin >> N >> H;
  a.resize(N), b.resize(N);
  long long aMax = 0;
  for (long long(i) = (0); (i) < (N); ++(i)) {
    cin >> a[i] >> b[i];
    chmax(aMax, a[i]);
  }
  vector<long long> bCand;
  for (long long(i) = (0); (i) < (N); ++(i)) {
    if (b[i] > aMax) {
      bCand.push_back(b[i]);
    }
  }
  long long cnt = 0;
  for (long long(i) = (0); (i) < (bCand.size()); ++(i)) {
    H -= bCand[i];
    cnt++;
    if (H <= 0) {
      cout << cnt << endl;
      return 0;
    }
  }
  cnt += (H + (aMax - 1)) / aMax;
  cout << cnt << endl;
  return 0;
}
