#include <iostream>
#include <cstdio>

using namespace std;

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

    double x[12][12];
    for(int i = 0; i < 12; i++)
        for(int j = 0; j < 12; j++)
            cin >> x[i][j];

    double sum = 0, cnt = 0;
    for(int i = 7; i <= 11; i++)
        for(int j = 12 - i; j <= i - 1; j++)
        {
            sum += x[i][j];
            cnt += 1;
        }

    if (t == 'M') sum /= cnt;
    printf("%.1lf", sum);

    return 0;
}