#include <cstdio>

int main() {
    char c;
    double sum = 0, arr[15][15];
    c = getchar();
    for(int i = 0; i < 12; ++i)
        for(int j = 0; j < 12; ++j)
            scanf("%lf", &arr[i][j]);

#if 0           // 中间切开到左右端点
    for(int i = 7, mid1 = 5, mid2 = 6; i <= 11; ++i) {
        for(int j = mid1; j > 11 - i; --j) sum += arr[i][j];
        for(int j = mid2; j < i; ++j) sum += arr[i][j];
    }
    printf("%.1lf\n", c == 'S' ? sum : sum / ((2 + 10) * 5 / 2));
#endif 

#if 1           // 确定左右端点
    sum = 0;
    for (int i = 7; i < 12; ++i)
        for (int j = 12 - i; j < i; ++j)
            sum += arr[i][j];
    printf("%.1lf\n", c == 'S' ? sum : sum / ((2 + 10) * 5 / 2));
#endif        
    return 0;
}