#include <iostream>
using namespace std;

int main(void){
    int N, i, *A;
    float ans;

    cin >> N;
    A = (int*)calloc(N, sizeof(int));
    for(i=0; i<N; i++) cin >> A[i];
    qsort(A, N, sizeof(*A), [](const void *a, const void *b){return *(int*)a - *(int*)b;});
    ans = N%2 ? A[N/2] : (A[N/2-1]+A[N/2])/2.;
    cout << ans << endl;

    free(A);
    return 0;
}