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