#include <iostream>

using namespace std;

int main(){
    int C;
    double num,sum = 0;
    char oper;
    cin >> C >> oper;
    for (int i = 0 ;i < 12;i++){
        for (int j = 0;j < 12; j++){
            cin >> num;
            if (j == C) sum += num;
        }
    }
    printf("%.1lf",oper == 'S'? sum:sum/12);
    return 0;
}