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

#define ELEM_SWAP(a,b) { register elem_type t=(a);(a)=(b);(b)=t; }
#define median(a,n) kth_smallest(a,n,(((n)&1)?((n)/2):(((n)/2)-1))) 

typedef float elem_type ;

elem_type kth_smallest(elem_type a[], int n, int k)
{
    register i,j,l,m ;
    register elem_type x ;
    l=0 ; m=n-1 ;
    while (l<m) {
       x=a[k] ;
       i=l ;
       j=m ;
       do {
          while (a[i]<x) i++ ;
          while (x<a[j]) j-- ;
          if (i<=j) {
             ELEM_SWAP(a[i],a[j]) ;
             i++ ; j-- ;
          }
       } while (i<=j) ;
       if (j<k) l=i ;
       if (k<i) m=j ;
  }
																			        return a[k] ;
}

int main(int argc, char ** argv)
{
	elem_type a[1000];
 	FILE *fwirth;
        int i;
	int size;
	elem_type result;
	int kapa;

	if (argc != 2) {
           printf("Correct usage: ./heap file_name (linux) or heap file_name (windows)\n");
           exit(1);
        }
        
	fwirth = fopen(argv[1], "r");
	if (fwirth == NULL) {
	   printf("Cannot open data file\n");
	   exit(0);
	}
        fscanf(fwirth, "%d", &size);
	printf("%d\n", size);
	for (i = 0; i < size; i++) fscanf(fwirth, "%f", &a[i]);

	kapa = size / 2;
	printf("%d\n", kapa);
	result = median(a, size/2);
	printf("%f\n", median(a,size));
   
}