N=int(input())
ans=0
L=list(map(int,input().split()))
L=[i-1 for i in L]
ind=[-1]*N
ans=0
for i in range(N):
  ind[L[i]]=i
for i in range(N):
  if L[i]==i:
    continue
  else:
    for j in range(L[i]-1,i-1,-1):
      #L[i]とL[i]-1を入れ替える
      #ind[j]はL[i]になる
      a,b=L[i],j
      L[i],L[ind[j]],ind[j],ind[L[i]]=L[ind[j]],L[i],ind[L[i]],ind[j]
      ind[a],ind[b]=ind[b],ind[a]
      ans+=1
print(ans)