Paint board

n = int(input())
a = [0] + [int(x) for x in input().split()]
dp = [0] * 101
dp[4] = dp[2] = dp[3] = dp[1] = 0

for i in range(5, n+1):
    dp[i] = max(dp[i-5] + a[i-4] + a[i-3] + a[i-2] + a[i-1] + a[i], dp[i-1])

print(dp[n] * 10)