public static string twoArrays(int k, List<int> A, List<int> B)
    {
        int[] a_arr = A.Order().ToArray();
        int[] b_arr = B.OrderDescending().ToArray();
        
        for(int i = 0; i < a_arr.Length; i++){
            if(a_arr[i] + b_arr[i] < k) return "NO";
        }
        
        return "YES";

    }