#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
string dbmc = "\033[1;38;2;57;197;187m", dbrs = "\033[0m";
#define debug(x...) cout << dbmc << "[" << #x << "] : ", dout(x)
void dout() { cout << dbrs << endl; }
template <typename T, typename ...U>
void dout(T t, U ...u) { cout << t << (sizeof...(u) ? ", " : ""); dout(u...); }
#else
#define debug(...) 0
#endif
#define ll long long
#define pll pair<ll,ll>
#define pii pair<int,int>
#define fs first
#define sc second
#define tiii tuple<int,int,int>
#define tlll tuple<ll,ll,ll>
#define ld long double
int main(){
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int n;
cin>>n;
vector<ld> v(n);
for(auto &i:v)cin>>i;
sort(v.begin(),v.end());
ld ans = v[0];
for(int i = 1;i<n;i++)ans = (ans+v[i])/2;
cout<<fixed<<setprecision(20)<<ans<<'\n';
return 0;
}
