https://www.acmicpc.net/problem/21758
n=int(input())
mlist=list(map(int, input().split()))
s=sum(mlist)
mx=0
b=mlist[0]
for i in range(1,n-1):
b+=mlist[i]
mx=max(mx, 2*s-mlist[0]-mlist[i]-b)
b=mlist[-1]
for i in range(n-2, 0,-1):
b+=mlist[i]
mx=max(mx, 2*s-mlist[-1]-mlist[i]-b)
for i in range(1, n-1):
mx=max(mx, s-mlist[0]-mlist[-1]+mlist[i])
print(mx)