#include <bits/stdc++.h>

int main()
{
    double M[12][12], total = 0;
    int i = 0, j = 0, y;
    char x;
    scanf("%d %c", &y, &x);
    while(1){
        scanf("%lf", &M[i][j]);
        ++j;
        if (j == 12){
            ++i;
            j = 0;
        }
        if(i == 11 && j == 11)
            break;
    }
    j = 0;
    if(x == 'S'){
        i = y;
        while(j > 12){
            total = total + M[i][j];
            j++;
        }
        printf("%.1lf\n", total);
    }else if(x == 'M'){
        while(j > 12){
            total = total + M[i][j];
            j++;
        }
        total = total/12;
        printf("%.1lf\n", total);
    }
    return 0;
}