#include <bits/stdc++.h>
using namespace std;
long long MOD = 1000000007;
int main() {
  int N;
  long long H;
  cin >> N >> H;
  vector<pair<long long, long long> > A;
  for (int i = 0; i < N; i++) {
    int a, b;
    cin >> a >> b;
    A.push_back(make_pair(b, a));
  }
  sort(A.begin(), A.end(), greater<pair<long long, long long> >());
  long long ans = 0;
  for (int i = 0; i < N; i++) {
    H -= A[i].first;
    ans++;
    if (H <= 0) {
      break;
    }
    if (i == N - 1 || A[i].second >= A[i + 1].first) {
      ans += (H / A[i].second) + ((H % A[i].second) ? 1 : 0);
      break;
    }
  }
  cout << ans << endl;
  return 0;
}
