#include<iostream>
#include<cstdio>

using namespace std;

int main()
{
    char x;
    cin >> x;

    double M[12][12] = {0};
    double n;
    for (int i = 0; i < 12;i ++)
    {
        for (int j = 0; j < 12;j ++)
        {
            cin >> n;
            M[i][j] = n;
        }
    }

    double sum = 0;
    for (int i = 1; i < 11; i ++)
    {
        for (int j = 0 ;j < i && j < 11 - i;j ++)
        {
                sum += M[i][j];
        }
    }

    if (x == 'S') printf("%.1lf", sum);
    else if( x == 'M') printf("%.1lf", sum/30);

    return 0;
}