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

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

#define mygc(c) (c)=getchar_unlocked()
void reader(int *x){int k,m=0;*x=0;for(;;){mygc(k);if(k=='-'){m=1;break;}if('0'<=k&&k<='9'){*x=k-'0';break;}}for(;;){mygc(k);if(k<'0'||k>'9')break;*x=(*x)*10+k-'0';}if(m)(*x)=-(*x);}

int N, A[1000];

int main(){
  int i;
  double res;

  reader(&N);
  rep(i,N) reader(A+i);
  sort(A,A+N);

  if(N%2) res = A[N/2]; else res = ((double)A[N/2]+A[N/2-1])/2;
  printf("%.1f\n", res);

  return 0;
}