#include <bits/stdc++.h>
using namespace std;
long long N, H;
vector<long long> a, b;
long long max_vec(vector<long long> v) {
  long long ans = 0;
  for (auto e : v) {
    ans = max(ans, e);
  }
  return ans;
}
int solve() {
  long long count = 0;
  long long max = max_vec(a);
  for (auto e : b) {
    if (max < e) {
      H -= e;
      count++;
      if (H <= 0) {
        cout << count << endl;
        return 0;
      }
    }
  }
  if (H % max == 0)
    count += H / max;
  else
    count += H / max + 1;
  cout << count << endl;
  return 0;
}
int main() {
  cin >> N >> H;
  a.resize(N);
  b.resize(N);
  for (int i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  solve();
  return 0;
}
