#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#define each(it,o) for(auto it= (o).begin(); it != (o).end(); ++ it)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define inrep int t;cin>>t; while(t--)
using namespace std;
using namespace __gnu_pbds; 


typedef long long int ll;
typedef vector<int> vi;
typedef pair<int,int> pii;
typedef vector<pii > vpii;
typedef vector<ll> vll;
typedef pair<ll,ll> pll;
typedef vector<pll > vpll; 
typedef vector<string> vs;
typedef long double ld;
const ll MOD = 1e9+7;
template<typename T> istream& operator>> ( istream &in,vector<T> &v ) {

    for ( unsigned   i=0; i<v.size(); i++ )
        in>>v[i];
    return in;
}
int main()
// {
//     #ifndef ONLINE_JUDGE
//     freopen("input.txt","r",stdin);
//     freopen("output.txt","w",stdout);
//     #endif
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n;
    cin>>n;
    double v[n];
    for(int i=0;i<n;i++)
    {
        cin>>v[i];
    }
    sort(v,v+n);double s=v[0];
    for(int i=1;i<n;i++)
    {
        s = (s+v[i])/2;
    }
    cout<<s;
    // #ifndef ONLINE_JUDGE
    //     cout<<"\nTime Elapsed : "<< 1.0*clock() / CLOCKS_PER_SEC << " s\n";
    // #endif
    
    return 0;
}