#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using P = pair<ll, ll>;
int main() {
  ll N, H;
  cin >> N >> H;
  vector<ll> v1(N), v2(N);
  for (ll i = 0; i < (ll)N; i++) {
    cin >> v1[i] >> v2[i];
  }
  ll v1max = 0;
  ll res = 0, sum = 0;
  for (ll i = 0; i < (ll)N; i++) {
    if (v1[i] > v1max) {
      v1max = v1[i];
    }
  }
  sort(v2.begin(), v2.end());
  reverse(v2.begin(), v2.end());
  for (ll i = 0; i < (ll)N; i++) {
    if (v2[i] < v1max || sum >= H)
      break;
    else {
      sum += v2[i];
      res++;
    }
  }
  if (sum < H) {
    sum += v1max;
    res += (H - sum) / v1max;
    res++;
  }
  cout << res << endl;
}
