#include <bits/stdc++.h>
using namespace std;
const int INF = 1 << 30;
const long long LINF = 1LL << 50;
const int NIL = -1;
const int MAX = 10000;
const int mod = 1000000007;
const double pi = 3.141592653589;
int main() {
  int N;
  long long H;
  cin >> N >> H;
  vector<pair<int, int> > v(N);
  for (int i = 0; i < N; i++) {
    int a, b;
    cin >> a >> b;
    v[i] = pair<int, int>(a, b);
  }
  sort(v.rbegin(), v.rend());
  int aMax = v[0].first;
  int ans = 0;
  for (int i = 0; 0 < H && i < N; i++) {
    if (aMax < v[i].second) {
      H -= v[i].second;
      ans++;
    }
  }
  if (H > 0) {
    ans += (H + aMax - 1) / aMax;
  }
  cout << ans << '\n';
}
