https://www.acmicpc.net/problem/11055
n=int(input())
mlist=list(map(int, input().split()))
dp=[0]*n
dp[0]=mlist[0]
for i in range(n):
for j in range(i):
if mlist[i]>mlist[j]:
dp[i]=max(dp[i], mlist[i]+dp[j])
else:
dp[i]=max(dp[i], mlist[i])
print(max(dp))