#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  cin >> N >> H;
  int a_max = 0;
  int a[100010], b[100010];
  for (int i = 1; i <= N; i++) {
    cin >> a[i] >> b[i];
    if (a[i] > a_max) a_max = a[i];
  }
  sort(b + 1, b + 1 + N, greater<int>());
  int ans = 0;
  for (int i = 1; i <= N; i++) {
    if (b[i] > a_max) {
      ans++;
      H -= b[i];
    } else
      break;
  }
  if (H % a_max == 0)
    ans += H / a_max;
  else
    ans += H / a_max + 1;
  cout << ans;
}
