n=int(input(""))
var=input("")
li=var.split(" ")
www=[]
pp=0
qq=0
for x in li:
    www.append(int(i))
if len(www)==1:
    print(0)
for y in range(1,len(www)) :
    for z in range(0,len(www)-1):
        if www[z]>www[z+1]:
            pp=www[z]
            www[z]=www[z+1]
            www[z+1]=pp
            qq+=1
print(qq)