#include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr int mo = 1e9 + 7;
constexpr int mod = mo;
constexpr int inf = 1 << 30;
int main() {
  int n, h;
  cin >> n >> h;
  vector<pair<int, int>> v(n);
  for (auto &a : v) cin >> a.first >> a.second;
  sort(v.begin(), v.end());
  reverse(v.begin(), v.end());
  int count = 0;
  for (int i = 0; i < n; ++i) {
    if (v[i].second > v[0].first) h -= v[i].second, count++;
    if (h <= 0) break;
  }
  if (h > 0) {
    count += (h + v[0].first - 1) / v[0].first;
  }
  cout << count << endl;
  return 0;
}
