n = int(input())
a = list(map(int, input().split()))

dp = [{} for x in range(n)]

def solve(i, w, get):
    if i >= n:
        return w

    if dp[i].get(w):
        return dp[i][w]
    dp[i][w] = w

    if get:
        return solve(i + 1, w, False)
    return max(solve(i + 1, w, False), solve(i + 1, w + a[i], True))

print(solve(0, 0, False))