n=int(input())
a=[int(i) for i in input().split(' ')]
b=a.copy()
f=b.copy()
for i in range(n-1):
    r=[]
    for i in range(n-i-1):
        r.append(max(f[i],f[i+1]))
    f=r.copy()
    b+=r
#print(b)
n=len(b)
f=b.copy()
for i in range(n-1):
    r=[]
    for i in range(n-i-1):
        r.append(max(f[i],f[i+1]))
    f=r.copy()
    b+=r
print(sum(b))