n = int(input())
P = list(map(int, input().split()))
Q = [0] * n
for i, p in enumerate(P, 1):
    Q[p - 1] = i
    
tot = 0
ans = 0
for i in range(n - 1):
    tot += Q[i]
    ans = max(ans, tot - Q[i + 1])
print(ans)