#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  cin >> N >> H;
  int MA = -1, A, B[100000];
  for (int i = 0; i < N; i++) {
    cin >> A >> B[i];
    MA = max(MA, A);
  }
  sort(B, B + N, greater<int>());
  int i = 0, cnt = 0;
  while (H > 0 && B[i] >= MA) {
    H -= B[i++];
    cnt++;
  }
  if (H) {
    cnt += (H + MA - 1) / MA;
  }
  cout << cnt << endl;
  return 0;
}
