[11052] 카드 구해보기

n = int(input())
data = [0] + list(map(int, input().split()))
dp = [0 for _ in range(n+1)]
for i in range(1, n+1):
    for j in range(1, i+1):
        dp[i] = max(dp[i], dp[i-j]+data[j])
print(dp[i])