#include <iostream>
using namespace std;
int main()
{
char c;
cin >> c;
double s = 0;
double a;
for (int i = 0;i < 12;i++)
{
for (int j = 0;j < 12;j++)
{
cin >> a;
if (j+i>11&&j>i)s += a;
}
}
if(c=='S')printf("%.1lf",s);
if(c=='M')printf("%.1lf",s/30);
}