N = int(input())
P = [0]+list(map(int,input().split()))
Col = [-1]*(N+1)
cnt = 0
for i in range(1,N+1):
    if Col[i]>=0:continue
    cur = i
    while Col[cur]<0:
        Col[cur] = cnt
        cur = P[cur]
    cnt += 1
C = {}
for i in range(1,N+1):
    if Col[i]>=0:
        C[Col[i]] = C.get(Col[i],0)+1
ans = 0
for c in C:
    ans += C[c]-1
print(ans)