#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, H;
  cin >> N >> H;
  int a[N], b[N];
  for (int i = 0; i < N; i++) cin >> a[i] >> b[i];
  sort(a, a + N);
  sort(b, b + N);
  reverse(b, b + N);
  int amax = a[N - 1];
  int dmg = 0;
  int cnt = 0;
  for (int i = 0; i < N; i++) {
    if (dmg < H && b[i] > amax) {
      dmg += b[i];
      cnt++;
    } else
      break;
  }
  int res = H - dmg;
  cnt += (res + amax - 1) / amax;
  cout << cnt << endl;
  return 0;
}
