n = int(input())
p = list(map(int, input().split()))
ord = [0] * n
for i, x in enumerate(p, 1):
    ord[x - 1] = i

ans = 0
now = 0
for i in range(n - 1):
    now += ord[i] - ord[i + 1]
    ans = max(ans, now)
    now += ord[i + 1]
print(ans)