N=int(input())
M=[int(input()) for _ in range(N)]
def bSort(a):
  ans=0
  for i in range(len(a)):
    for j in range(len(a)-1, i, -1):
      if a[j] < a[j-1]:
        ans+=1     
        a[j], a[j-1] = a[j-1], a[j]
  return ans
print(bSort(M))