#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5;
int N, H;
int a, b[MAXN];
int main() {
  cin >> N >> H;
  int ma = 0;
  for (int i = 0; i < N; i++) {
    cin >> a >> b[i];
    if (ma < a) ma = a;
  }
  sort(b, b + N, greater<int>());
  int cnt = 0;
  for (int i = 0; i < N; i++) {
    if (b[i] < ma) break;
    H -= b[i];
    cnt++;
  }
  cnt += (H + ma - 1) / ma;
  cout << cnt << endl;
  return 0;
}
