#include <iostream>
#include <cmath>
#include <vector>
#include <algorithm>
#define REP(i, n) for(int i = 0; i < (int)(n); i++)
#define print(x) cout << x << endl;
using namespace std;
int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    int N;
    cin >> N;
    vector<int> A(N);
    REP(i, N) cin >> A[i];
    sort(A.begin(), A.end());
    
    int d;
    float ans;
    if(N%2==0){
        d = N/2;
        ans = (A[d]+A[d-1])/2.0;
    }else{
        d = N/2;
        ans = A[d];
    }
    print(ans);
    return 0;
}