#include <bits/stdc++.h>
using namespace std;
const long long MAX = 1e5 + 10;
bool cmp(pair<long long, long long> l, pair<long long, long long> r) {
  return l.second <= r.second;
}
long long main() {
  long long n, h;
  cin >> n >> h;
  long long s = 0;
  pair<long long, long long> p[MAX];
  for (long long i = 0; i < n; i++) {
    cin >> p[i].first >> p[i].second;
    s += p[i].second;
  }
  if (s >= h) {
    sort(p, p + n, cmp);
    for (long long i = n - 1; i >= 0; i--) {
      h -= p[i].second;
      if (h <= 0) {
        cout << n - i;
        return 0;
      }
    }
  }
  sort(p, p + n);
  long long a = p[n - 1].first;
  h -= s;
  long long t = (h / a) + 1;
  if (h % a == 0) t--;
  cout << n + t;
}
