#include <cstdio>
int main()
{
char op;
int cnt = 0;
double s = 0;
scanf("%c", &op);
double a[12][12];
for (int i = 0; i < 12; i ++ )
for (int j = 0; j < 12; j ++ )
scanf("%lf", &a[i][j]);
for (int i = 7; i < 12; i ++ ) //除了左方和右方之外都是一步到位
for (int j = 12 - i; j < i; j ++ )
{
s += a[i][j];
cnt ++ ;
}
if (op == 'S') printf("%.1lf\n", s);
else printf("%.1lf\n", s / cnt);
return 0;
}