#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  cin >> N >> H;
  vector<long long> A(N), B(N);
  long long amax = 0;
  for (int i = 0; i < (int)(N); i++) {
    cin >> A[i] >> B[i];
    amax = max(amax, A[i]);
  }
  priority_queue<long long> pq;
  for (int i = 0; i < (int)(N); i++) {
    pq.push(B[i]);
  }
  long long cnt = H / amax;
  if (H % amax != 0) cnt++;
  long long fcnt = cnt;
  long long damage = cnt * amax;
  long long throw_sum = 0;
  int throw_cnt = 0;
  for (int i = 0; i < N; i++) {
    long long x = pq.top();
    pq.pop();
    if (x <= amax) break;
    throw_sum += x;
    throw_cnt++;
    int tmpcnt1 = throw_sum / amax;
    cnt = min(cnt, fcnt - tmpcnt1 + throw_cnt);
    if (throw_sum % amax != 0) {
      int tmpcnt2 = throw_sum / amax + 1;
      if (damage - tmpcnt2 * amax + throw_sum >= H) {
        long long aaa = min(fcnt, throw_sum / amax + 1);
        cnt = min(cnt, fcnt - aaa + throw_cnt);
      }
    }
  }
  cout << cnt << endl;
}
