#include <stdio.h>

int n;
int a[1000];
int b[1000];

int z(void){
	int min,nb;
	min = a[0]; nb = 0;
	for(int i = 0;i < n;i++){
		if(min > a[i]) {
			min = a[i];
			nb = i;
		}
	}
	return(nb);
}
int main (void){
	int t,nb;  double ans;
	scanf("%d",&n); for(int i = 0;i < n;i++) scanf("%d",&a[i]);
		for(int i = 0;i < n;i++){
			nb = z();
			b[i] = a[nb];
			a[nb] = 1001;
		}

	if(n%2 == 1){
		t = n*0.5;
		ans = b[t];
	}else{
		t = n*0.5;
		ans = (b[t-1] + b[t])*0.5;
	}
	printf("%.1f\n",ans);
	return(0);
}