#include <bits/stdc++.h>
using namespace std;
long long n, h, b[101010];
signed main() {
  cin >> n >> h;
  long long ma = 0;
  for (long long i = 0; i < (long long)(n); i++) {
    long long a;
    cin >> a >> b[i];
    ma = max(ma, a);
  }
  sort(b, b + n, greater<long long>());
  long long res = 0;
  for (long long i = 0; i < (long long)(n); i++) {
    if (b[i] < ma || h <= 0) break;
    h -= b[i];
    res++;
  }
  res += (h + ma - 1) / ma;
  cout << res << endl;
}
