#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using vll = vector<long long>;
constexpr long long mod = 1000000007;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long n, h;
  cin >> n >> h;
  vector<pair<long long, long long>> v(n);
  for (int i = 0; i < n; i++) {
    long long t1, t2;
    cin >> t1 >> t2;
    v[i] = make_pair(t1, t2);
  }
  sort(v.begin(), v.end(), greater<pair<long long, long long>>());
  long long t = v[0].first;
  long long cnt = 0;
  long long sum = 0;
  for (int i = 0; i < n; i++) {
    if (t < v[i].second) {
      sum += v[i].second;
      cnt++;
    }
    if (sum >= h) {
      break;
    }
  }
  if (sum < h) {
    if ((h - sum) % t != 0) {
      cnt++;
    }
    cnt += (h - sum) / t;
  }
  cout << cnt << endl;
}
