#include <cstdio>
#include <algorithm>
using namespace std;
const int N = 100000 + 10;
int n, u, v, s, t, a[N], c[N];
int main() {
    freopen("circlea.in", "r", stdin);
    freopen("circlea.out", "w", stdout);
    scanf("%d", &n);
    for(int i=1; i<=n; i++) {
        scanf("%d", a+i);
        c[i] = c[i-1] + a[i];
    }
    while(v < n) {
        t = c[v] - c[u];
        //fprintf(stderr, "%d %d (%d)\n", v, u, t);
        s = max(s, min(t, c[n] - t));
        while(t <= c[n] - t && v < n) { v++;
            t = c[v] - c[u];
        //fprintf(stderr, "%d %d (%d)\n", v, u, t);
            s = max(s, min(t, c[n] - t));
        } u++;
    } printf("%d\n", s);
    return 0;
}