# include <stdio.h>
# include <stdlib.h>
# include <time.h>


double normal (void)
{
    int i;
    double sum = 0.0;


    for (i = 0; i < 12; i ++)
	sum += drand48 ( );

    return sum - 6.0;
}


int main (int argc, char *argv [])
{
    int i, n;

    n = (argc > 1 ? atoi (argv [1]) : 1);
    srand48 (time (NULL));

    for (i = 0; i < n; i ++)
	printf ("%g\n", normal ( ));

    return 0;
}