#include <bits/stdc++.h>
const double PI =
    3.141592653589793238462643383279502884197169399375105820974944;
using namespace std;
void solve() {
  long long n, h;
  cin >> n >> h;
  vector<pair<long long, long long> > vec(n);
  long long sum = 0;
  for (long long i = 0; i < n; ++i) {
    long long a, b;
    cin >> a >> b;
    vec[i] = make_pair(a, b);
  }
  sort(vec.begin(), vec.end());
  long long count = 0;
  for (long long i = 0; i < n; ++i) {
    if (vec[i].second > vec[n - 1].first) {
      ++count;
      sum += vec[i].second;
    }
  }
  long long ans1 = (h - sum) / vec[n - 1].first;
  if ((h - sum) % vec[n - 1].first != 0) ans1++;
  printf("%lld\n", ans1 + count);
}
int main() {
  bool testing = false;
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  if (testing) {
    freopen("test.txt", "rt", stdin);
    int start = clock();
    solve();
    int end = clock();
    cout << "time: " << (end - start) / (double)(CLOCKS_PER_SEC)*1000
         << " milliseconds\n";
  } else {
    solve();
  }
}
