#include <iostream>
#include <iomanip>
using namespace std;
int main(){
int n;
double sum = 0;
char c;
cin >> n >> c;
double f[12][12];
for(int i = 0; i < 12; i++){
for(int j = 0; j < 12; j++){
cin >> f[i][j];
if(j == n) sum += f[i][j];
}
}
if(c=='S')printf("%.1lf",sum);
if(c=='M')printf("%.1lf",sum/12);
}