#include <bits/stdc++.h>
using namespace std;
int main() {
  long long i;
  long long N, H;
  long long result = 0;
  cin >> N >> H;
  vector<long long> A(N);
  vector<long long> B(N);
  for (i = 0; i < N; i++) cin >> A[i] >> B[i];
  sort(A.begin(), A.end(), greater<long long>());
  sort(B.begin(), B.end(), greater<long long>());
  for (i = 0; i < N; i++) {
    if (B[i] >= A[0]) {
      H -= B[i];
      result += 1;
    } else {
      break;
    }
    if (H <= 0) break;
  }
  if (H % A[0] == 0 || H <= 0) {
    result += H / A[0];
  } else {
    result += H / A[0] + 1;
  }
  cout << result << endl;
}
