#include<stdio.h>
#include<stdlib.h>
     
int main(void){
	int n,i,j,l,r,p,t=2,x;
	int *a,*s;

	scanf("%d",&n);
	a=(int*)malloc(sizeof(int)*n);
	s=(int*)malloc(sizeof(int)*n);
	s[0]=0;
	s[1]=n-1;

	for(i=0;i<n;i++){
		scanf("%d",&a[i]);
	}

	while(t>0){
		t-=2;
		i=l=s[t];
		j=r=s[t+1];
		p=a[i];
		while(i<=j){
			while(a[i]<p&&i<r) i++;
			while(a[j]>=p&&j>l) j--;
			if(i<=j){
				x=a[i];
				a[i]=a[j];
				a[j]=x;
				i++;
				j--;
			}
		}
		if(j>l){
			s[t]=l;
			s[t+1]=j;
			t+=2;
		}
		if(r>i){
			s[t]=i;
			s[t+1]=r;
			t+=2;
		}
	}

	printf("%g\n",(double)(a[(n-1)/2]+a[n/2])/2);

	return 0;
}