N,*V=map(int,open(0).read().split())
a=0
s=[0]*(N+1)
for i in range(N):
    if i+1!=V[i] and s[i+1]==0:
        c=i+1
        while V[c-1]!=i+1:
            c=V[c-1]
            s[c]=1
            a+=1
print(a)