#include <bits/stdc++.h>
#define int long long
#define endl "\n"
using namespace std;
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
int x[n+1], pf[n+1];
pf[0]=0;
for(int i=1; i<=n; ++i) {
cin >> x[i];
pf[i] = pf[i-1]+x[i];
}
int sf[n+2];
sf[n+1]=0;
for(int i=n; i>0; --i) sf[i] = sf[i+1]+x[i];
int k=(n+1)/2, ans=0;
for(int i=1; i<=n; ++i) {
if(i<k) {
int l = pf[i]+sf[n-(k-i-1)];
int r = pf[i+k-1]-pf[i-1];
ans = max(ans, min(l,r));
continue;
}
int l = pf[i]-pf[i-k];
int r;
if((i+k-1)>n) r = sf[i]+pf[k-(n-i+1)];
else r = pf[i+k-1]-pf[i-1];
ans = max(ans, min(l,r));
}
cout << ans << endl;
}
