#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
const int MAXN = 5e5+2;
int l[2*MAXN], r[2*MAXN], val[2*MAXN];
int sums[MAXN];
int n;
int currInd = 0;
void build(int v = 1) {
if (v < n) {
build(v*2);
build(v*2+1);
l[v] = l[v*2];
r[v] = r[v*2+1];
val[v] = min(val[v*2], val[v*2+1]);
} else {
l[v] = currInd;
r[v] = currInd;
val[v] = sums[currInd++];
}
}
int query(int L, int R, int v = 1) {
if (R < l[v] || r[v] < L) {
return INT32_MAX;
} else if (L <= l[v] && r[v] <= R) {
return val[v];
} else {
return min(query(L, R, v*2), query(L, R, v*2+1));
}
}
signed main() {
cin >> n;
int a[n];
int sum = 0;
int half = (n+1)/2;
for (int i = 0; i < n; i++) {
cin >> a[i];
if (i < half) {
sum += a[i];
}
}
for (int i = 0; i <= n; i++) {
sums[i] = sum;
sum += a[(i+half)];
sum -= a[i];
}
build();
int ans = 0;
for (int i = 0; i < n; i++) {
int L = (i-half+1);
int R = i;
if (R < L) {
ans = max(ans, min(query(0, R), query(L, n-1)));
} else {
ans = max(ans, query(L, R));
}
}
cout << ans << endl;
}
