#include<bits/stdc++.h>
using namespace std;
int main(){
    int a[160]={0},n,i,h=1,j,k;
    float l,b,p;
    cin>>n;
    for(i=0;i<n;i++){
    	cin>>a[i];
    }
    for(h=1;h<n;h++){
    	for(i=0;i<n-h;i++){
    		if(a[i]>a[i+1]){
    			swap(a[i],a[i+1]);
    		}
    	}
    }
    if(n%2==1){
    	b=n/2;
		p=a[n/2]*1.0;
	    printf("%.1f",p);
    }else{
    	j=n/2-1;
    	k=n/2;
    	l=(a[j]+a[k])/2.0;
    	printf("%.1f",l);
    }
    
}
/**************************************************************
	Problem: 1233
	User: huanghengyi
	Language: C++
	Result: Accepted
	Time:9 ms
	Memory:2076 kb
****************************************************************/