#include <bits/stdc++.h>
using namespace std;
int main() {
  long long N, H;
  cin >> N >> H;
  long long B[100005];
  long long a_max = 1;
  for (long long i = 0; i < N; i++) {
    long long a, b;
    cin >> a >> b;
    a_max = max(a_max, a);
    B[i] = b;
  }
  sort(B, B + N);
  long long sum = 0, cnt = 0;
  for (long long i = N - 1; i >= 0; i--) {
    if (B[i] >= a_max) {
      sum += B[i];
      cnt++;
    } else
      break;
  }
  H -= sum;
  cnt += (H + (a_max - 1)) / a_max;
  cout << cnt << endl;
  return 0;
}
