#include <bits/stdc++.h>
using namespace std;
const int INF = 10000000LL;
int N, H, ans = 0, ma = 0;
int a[100000], b[100000];
pair<int, int> C[35][35];
int main() {
  cin >> N >> H;
  for (int i = 0; i < N; ++i) {
    cin >> a[i] >> b[i];
    ma = max(ma, a[i]);
  }
  for (int i = 0; i < N; ++i) {
    if (b[i] > ma) {
      H -= b[i];
      ans++;
      if (H <= 0) break;
    }
  }
  ans += H / ma;
  if (H % ma > 0) ++ans;
  cout << ans << endl;
  return 0;
}
