#include <bits/stdc++.h>
using namespace std;
vector<pair<int, int> > v;
int n, a, b, h, ind, suf[100005], ans, k;
int main() {
  cin >> n >> h;
  ans = 1e9;
  for (int i = 1; i <= n; ++i) {
    cin >> a >> b;
    v.push_back(make_pair(b, a));
  }
  sort(v.begin(), v.end());
  suf[(int)v.size() - 1] = v[(int)v.size() - 1].first;
  for (int i = (int)v.size() - 2; i >= 0; --i) {
    suf[i] = suf[i + 1] + v[i].first;
  }
  for (int i = (int)v.size() - 1; i >= 0; --i) {
    ind =
        lower_bound(v.begin(), v.end(), make_pair(v[i].second, -1)) - v.begin();
    if ((h - suf[ind]) % v[i].second == 0) {
      k = (h - suf[ind]) / v[i].second;
    } else {
      k = (h - suf[ind]) / v[i].second + 1;
    }
    ans = min(ans, n - ind + k);
  }
  if (suf[0] >= h) {
    ans = min(ans, n);
  }
  cout << ans << endl;
  return 0;
}
