#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, h, a, b, mx = -1, p = 0, c, life, dead = 0;
  cin >> n >> h;
  vector<long long> k;
  vector<long long> th;
  for (long long i = 0; i < n; i++) {
    cin >> a >> b;
    k.push_back(a);
    if (a > mx) {
      mx = a;
      p = i;
    }
    th.push_back(b);
  }
  mx = th[p];
  if (th[p] < k[p]) {
    mx = k[p];
  }
  c = 0;
  life = h;
  sort(th.begin(), th.end(), greater<int>());
  for (unsigned int i = 0; i < n; i++) {
    if (th[i] < mx) break;
    life -= th[i];
    c++;
    if (life <= 0) {
      cout << c << endl;
      return 0;
    }
  }
  c += ceil(life * 1.00 / k[p]);
  cout << c << endl;
  return 0;
}
