#include <bits/stdc++.h>
using namespace std;
const long long P = 1000000007;
int gcd(int a, int b) { return b != 0 ? gcd(b, a % b) : a; }
int lcm(int a, int b) { return a / gcd(a, b) * b; }
int main() {
  long long N, H;
  cin >> N >> H;
  vector<long long> a(N), b(N);
  long long damagecount = 0;
  for (int i = (0); i < (N); ++i) cin >> a[i] >> b[i];
  vector<pair<long long, long long>> katana;
  for (int i = (0); i < (N); ++i) {
    katana.push_back(make_pair(a[i], b[i]));
  }
  sort((katana).rbegin(), (katana).rend());
  for (int i = (0); i < (N); ++i) {
    if (H <= katana[0].second) {
      H = 0;
      damagecount++;
      cout << damagecount << endl;
      return 0;
    }
    if (i != 0 && katana[i].second >= katana[0].first) {
      H -= katana[i].second;
      damagecount++;
      katana[i].second = 0;
    }
  }
  for (long long i = 0; i < 1000000000; i++) {
    if (H <= katana[0].second) {
      H = 0;
      damagecount++;
      cout << damagecount << endl;
      return 0;
    } else {
      H -= katana[0].first;
      damagecount++;
    }
  }
  return 0;
}
