#include <bits/stdc++.h>
using namespace std;
int main(void) {
  long long N, H;
  cin >> N >> H;
  vector<vector<long long>> ab(2, vector<long long>(N));
  for (int i = 0; i < N; i++) {
    long long a, b;
    cin >> a >> b;
    ab[0][i] = a;
    ab[1][i] = b;
  }
  sort(ab[0].begin(), ab[0].end());
  sort(ab[1].begin(), ab[1].end());
  long long count = 0;
  for (int i = 0; i < N; i++) {
    if (ab[0][N - 1] < ab[1][N - i - 1])
      H -= ab[1][N - i - 1];
    else
      break;
    count++;
    if (H < 0) break;
  }
  if (H < 0)
    cout << count;
  else
    cout << count + (H + (ab[0][N - 1] - 1)) / ab[0][N - 1];
}
