#include <bits/stdc++.h>
using namespace std;

signed main(){
  int N; cin >> N;
  vector< int > A( N );
  for( int i = 0; i < N; ++i )
    cin >> A[ i ];
  sort( A.begin(), A.end() );
  if( N & 1 )
    cout << A[ N / 2 ] << endl;
  else{
    int t = A[ N / 2 - 1 ] + A[ N / 2 ];
    cout << t / 2;
    if( t & 1 )
      cout << ".5";
    cout << endl;
  }
  return 0;
}