n = int(input())
suzu = list(map(int, input().split()))
ans = 0
draw = 0
for i in range(n, 1, -1):
    smax = suzu.index(i) + 1
    pt = sum([i+1 for i in range(n)]) - smax*2 - draw
    ans = pt if ans < pt else ans
    draw += smax
print (ans)