#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
const int N = 2e5+100;
int ans[N], a[N];
signed main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);
int ls=0;
int n;cin >> n;
for(int i=0 ; i<n ; i++){
cin >> a[i];
ans[i] = a[i];
}
for(int i=0 ; i<n ; i++){
ans[i] += ls;
ls += a[i];
ls /= 2;
}
ls = 0;
for(int i=n-1 ; i>=0 ; i--){
ans[i] += ls;
ls += a[i];
ls /= 2;
}
cout << *max_element(ans, ans+n) << "\n";
}
{"html5":"htmlmixed","css":"css","javascript":"javascript","php":"php","python":"python","ruby":"ruby","lua":"text\/x-lua","bash":"text\/x-sh","go":"go","c":"text\/x-csrc","cpp":"text\/x-c++src","diff":"diff","latex":"stex","sql":"sql","xml":"xml","apl":"apl","asterisk":"asterisk","c_loadrunner":"text\/x-csrc","c_mac":"text\/x-csrc","coffeescript":"text\/x-coffeescript","csharp":"text\/x-csharp","d":"d","ecmascript":"javascript","erlang":"erlang","groovy":"text\/x-groovy","haskell":"text\/x-haskell","haxe":"text\/x-haxe","html4strict":"htmlmixed","java":"text\/x-java","java5":"text\/x-java","jquery":"javascript","mirc":"mirc","mysql":"sql","ocaml":"text\/x-ocaml","pascal":"text\/x-pascal","perl":"perl","perl6":"perl","plsql":"sql","properties":"text\/x-properties","q":"text\/x-q","scala":"scala","scheme":"text\/x-scheme","tcl":"text\/x-tcl","vb":"text\/x-vb","verilog":"text\/x-verilog","yaml":"text\/x-yaml","z80":"text\/x-z80"}
