#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
char c;
cin >> c;
double m[12][12];
for (int i = 0; i < 12; i ++ )
for (int j = 0; j < 12; j ++ )
cin >> m[i][j];
double s = 0;
int t = 0;
for (int i = 1; i < 12; i ++ )
for (int j = 12 - i; j < 12; j ++ , t ++ )
s += m[i][j];
if (c == 'S') printf("%.1lf", s);
else printf("%.1lf", s / t);
return 0;
}