#include <bits/stdc++.h>
using namespace std;
int main() {
  int N;
  int H;
  cin >> N >> H;
  int a[100000];
  int b[100000];
  int num = 0;
  int a_max = 0;
  for (num = 0; num < N; num++) {
    cin >> a[num] >> b[num];
    if (a[num] > a_max) {
      a_max = a[num];
    }
  }
  int result = 0;
  for (num = 0; num < N; num++) {
    if (b[num] > a_max) {
      result = result + 1;
      H = H - b[num];
    }
  }
  if (H % a_max != 0) result = result + 1;
  result = result + (H / a_max);
  cout << result << endl;
  return 0;
}
