#include <bits/stdc++.h>
using namespace std;
int sum, cunt2, cunt, N, H;
static const int MAX = 10000;
pair<int, int> ab[MAX];
void solve() {
  sort(ab, ab + N);
  if (sum >= H) {
    cout << N << "\n";
    return;
  }
  if ((H - sum) % ab[N - 1].first)
    cunt2 = N + (H - sum) / ab[N - 1].first;
  else
    cunt2 = N + (H - sum) / ab[N - 1].first - 1;
  cout << cunt2 << "\n";
}
int main() {
  cin >> N >> H;
  for (int i = 0; i < N; i++) {
    cin >> ab[i].first >> ab[i].second;
    sum += ab[i].second;
  }
  solve();
  return 0;
}
