#include <vector>
#include <algorithm>
#include <iostream>
typedef unsigned long number;
int main ()
{
int size;
std::vector<number> data;
data.reserve (250000);
std::cin >> size;
for ( int i=0; i<size; ++i ) {
data.push_back (0);
std::cin >> data[i];
}
std::sort ( data.begin(), data.end() );
if ( size%2 ) {
std::cout << data[(size+1)/2-1];
} else {
number l = data[size/2-1];
number r = data[size/2];
switch ( (l%2) + (r%2) ) {
case 0: std::cout << l/2+r/2; break;
case 1: std::cout << l/2+r/2 << ".5"; break;
case 2: std::cout << l/2+r/2+1; break;
}
}
return 0;
}
