#include <bits/stdc++.h>
using namespace std;
long long n, h, a[100005], b[100005];
signed main() {
  cin >> n >> h;
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  sort(a, a + n);
  sort(b, b + n);
  long long mx = a[n - 1];
  long long katana = n - 1;
  long long cnt = 0;
  while (katana >= 0 && b[katana] > mx && h > 0) {
    h -= b[katana];
    katana--;
    cnt++;
  }
  cout << cnt + (h + mx - 1) / mx << endl;
  return 0;
}
