#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long N, H, MaxA = 0, ans;
  cin >> N >> H;
  vector<long long> b(N);
  for (int i = 0; i < (int)(N); i++) {
    long long a;
    cin >> a >> b.at(i);
    MaxA = max(MaxA, a);
  }
  long long SumB = 0, cnt = 0;
  sort(b.begin(), b.end());
  for (int i = 0; i < (int)(N); i++) {
    if (b.at(i) > MaxA) {
      SumB += b.at(i);
      cnt++;
    }
    if (SumB >= H) break;
  }
  if (H - SumB <= 0) {
    cout << cnt << endl;
  } else if ((H - SumB) % MaxA == 0) {
    cout << (H - SumB) / MaxA + cnt << endl;
  } else {
    cout << (H - SumB) / MaxA + cnt + 1 << endl;
  }
}
