n = int(input())
arr = list(map(int, input().split()))
dp = [0]*n
dp[0] = arr[0]
for i in range(1, n):
for j in range(i):
if arr[i] > arr[j]:
dp[i] = max(dp[i], dp[j]+arr[i])
else:
dp[i] = max(dp[i], arr[i])
print(max(dp))