using System;

public class Program

{

    public static void Main()

    {

        char o;

    int i, j, aux = 1;

    double s = 0, n;

    o =Convert.ToChar(Console.ReadLine());

    for (i = 0; i <= 4; i++){

        for (j = 0; j <= 11; j++){

            n = Convert.ToDouble(Console.ReadLine());

            if (j >= aux && j <= 11 - aux)

                s += n;

        }

        aux++;

    }

    if (o == 'S')

        Console.WriteLine(s.ToString("0.0"));

    else

        Console.WriteLine(( s / 30).ToString("0.0"));;

    }

}