#include <bits/stdc++.h>
using namespace std;
constexpr long long INF = numeric_limits<long long>::max() / 2;
constexpr long long INFL = numeric_limits<long long>::max() / 2;
constexpr long long MOD = 1000000007;
using Graph = vector<vector<long long>>;
signed main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  long long N, H;
  cin >> N >> H;
  long long a[N], b[N];
  long long am = 0;
  for (long long i = 0; i < (long long)(N); i++) {
    cin >> a[i] >> b[i];
    am = max(am, a[i]);
  }
  sort(b, b + N);
  reverse(b, b + N);
  long long ans = 0;
  for (long long i = 0; i < (long long)(N); i++) {
    if (b[i] > am) {
      H -= b[i];
      ans++;
    } else
      break;
    if (H <= 0) break;
  }
  long long x = (H + am - 1) / am;
  cout << ans + x << endl;
}
