#include <bits/stdc++.h>
using namespace std;
using vi = vector<int>;
using vvi = vector<vi>;
using ll = long long;
const int mod = 1e9 + 9;
const int INF = 1e9;
int main() {
  ll n, h;
  cin >> n >> h;
  vector<ll> a(n), b(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a.begin(), a.end());
  ll A_MAX = a[n - 1];
  ll k = 0;
  ll cnt = 0;
  for (int i = 0; i < n; i++) {
    if (b[i] > A_MAX) {
      k += b[i];
      cnt++;
    }
  }
  h -= k;
  while (h > 0) {
    h -= A_MAX;
    cnt++;
  }
  cout << cnt << endl;
  return 0;
}
