#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
char rule;
cin>>rule;
double m[12][12];
double sum=0.0;
for(int i=0;i<12;i++)
{
for(int j=0;j<12;j++)
{
cin>>m[i][j];
if(i<j&&i+j<11)
sum+=m[i][j];
}
}
if(rule=='S')
printf("%.1lf\n",sum);
if(rule=='M')
printf("%.1lf\n",sum/30);
return 0;
}