n,*a=map(int,open(0).read().split())
INF=1<<60
ans=-INF
if 0 in a:
  ans=0
def f(K,T):
  ms=-INF
  s=smin=0
  ret=[]
  for i in a[::T]:
    s+=K*i
    ms=max(ms,s-smin)
    ret+=ms,
    smin=min(smin,s)
  return ret
l=f(1,1)
r=f(1,-1)[::-1]
for i,j in zip(l,r[1:]):
  ans=max(ans,i*j)
l=f(-1,1)
r=f(-1,-1)[::-1]
for i,j in zip(l,r[1:]):
  ans=max(ans,i*j)
print(ans)