n = int(input())
l = list(map(int,input().split()))
a = 0
for i in range(n-1):
    for m in range(n-1-i):
        if l[m] > l[m + 1]:
            l[m],l[m+1] = l[m+1],l[m]
            a += 1
print(a)

啊啊啊几个月前我就30分，现在还是30分，真是没长进 qwq