#include <bits/stdc++.h>
using namespace std;
long long mo = 1e9 + 7;
template <class T, class S>
void cmin(T &a, const S &b) {
  if (a > b) a = b;
}
template <class T, class S>
void cmax(T &a, const S &b) {
  if (a < b) a = b;
}
int main() {
  long long N, H;
  cin >> N >> H;
  vector<pair<long long, long long> > P(N);
  for (int i = 0; i < N; i++) {
    cin >> P[i].first >> P[i].second;
  }
  sort(P.begin(), P.end(), greater<pair<long long, long long> >());
  long long Ma = P[0].first;
  if (Ma >= P[0].second) {
    cout << (H + Ma - 1) / Ma << endl;
    return 0;
  }
  vector<long long> B;
  for (int i = 0; i < N; i++) {
    if (Ma < P[i].second) {
      B.push_back(P[i].second);
    }
  }
  long long cnt = 0;
  for (int i = 0; i < B.size(); i++) {
    H -= B[i];
    cnt++;
    if (H <= 0) {
      break;
    }
  }
  if (H <= 0) {
    cout << cnt << endl;
    return 0;
  }
  cnt += (H + Ma - 1) / Ma;
  cout << cnt << endl;
}
