#include <iostream>
using namespace std;
int main()
{
    double a[12][12],t = 0.0,cout = 0;
    string menu;
    cin >> menu;
    for (int i = 0 ;i<=11;i++)
    {
        for (int j = 0;j<=11;j++)
        cin >> a[i][j];
    }
    for (int i = 0 ;i <= 11; i++)
    {
        for (int j = 0;j<=11;j++)
        if(i + j >= 12) 
        {
            t += a[i][j];
            cout += 1 ;
        }
    }
    if (menu == "S") printf("%.1lf",t);
    else printf("%.1lf",t/cout);
}