#include <bits/stdc++.h>
using namespace std;
signed main() {
  long long n;
  long long h;
  cin >> n >> h;
  vector<long long> a(n), b(n);
  for (long long i = 0; i < n; i++) {
    cin >> a.at(i) >> b.at(i);
  }
  long long maxa = *max_element(begin(a), end(a));
  long long num = 0, sum = 0;
  for (auto &&w : b) {
    if (w > maxa) {
      sum += w;
      num++;
    }
  }
  long long numa = max(0ll, (((h - sum) + maxa - 1) / maxa));
  cout << num + numa << endl;
}
