#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  long long n, h, m = -1e18, ans = 0;
  cin >> n >> h;
  vector<long long> a(n), b(n);
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    m = max(m, a[i]);
  }
  sort(b.begin(), b.end());
  long long it = lower_bound(b.begin(), b.end(), m) - b.begin();
  for (int i = it; i < n; i++) {
    if (h > 0) {
      h -= b[i];
      ans++;
    } else
      break;
  }
  if (h > 0) {
    if (h % m == 0)
      ans += h / m;
    else
      ans += h / m + 1;
  }
  cout << ans << endl;
  return 0;
}
