#include <bits/stdc++.h>
using namespace std;
int n, h, a[100020], b[100020], ma, ans;
int main() {
  cin >> n >> h;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + n);
  ma = a[n - 1];
  sort(b, b + n);
  for (int j = 0; j < n; j++) {
    if (b[j] > ma && h > 0) {
      h -= b[j];
      ans++;
    }
  }
  if (h > 0) ans += (h + ma - 1) / ma;
  cout << ans << endl;
  system("pause");
  return 0;
}
