G

using System;
internal class ChristmasArray : BaseArray
{
    public ChristmasArray(int[] x) : base(x)
    {

    }
    public override int this[int number] {
        get {

            int ans = number;
            foreach (var i in array)
            {
                if (i < number && ((number-i)<(number-ans) || ans== number))
                {
                    ans = i;
                }
            }
            if (ans == number)
            {
                throw new ArgumentException("Number does not exist.");
            }
            return ans;
        }
    }

    public override double GetMetric()
    {
        int n = 0;
        int ans = 0;
        for(int i=0; i<array.Length; i++)
        {
            n += array[i].ToString().Length;
            int k = array[i];
            while (k > 0)
            {
                if (k % 10 == 6)
                {
                    ans++;
                }
                k /= 10;
            }
        }
        return ans*1.0 / n;
    }

}