N = int(input())
a = list(map(int,input().split()))
an = [a.index(i+1) for i in range(N)]

i = N-1
t = 0
count = 0
while True:
    if an[i] < an[i-1]:
        an = list(map(lambda x: x+1 if x <= i else x, an))
        an[i-1] = 0
        count += 1
        t = 1
    if i > 1:
        i -= 1
    else:
        if t == 0:
            break
        else:
            t = 0
            i = N-1
print(count)