import sys input = sys.stdin.readline N=int(input()) P=list(map(int,input().split())) # UnionFind Group = [i for i in range(N+1)] # グループ分け Nodes = [1]*(N+1) # 各グループのノードの数 def find(x): while Group[x] != x: x=Group[x] return x def Union(x,y): if find(x) != find(y): if Nodes[find(x)] < Nodes[find(y)]: Nodes[find(y)] += Nodes[find(x)] Nodes[find(x)] = 0 Group[find(x)] = find(y) else: Nodes[find(x)] += Nodes[find(y)] Nodes[find(y)] = 0 Group[find(y)] = find(x) for i in range(N): Union(i+1,P[i]) ANS=N for i in range(1,N): if find(i)==i: ANS-=1 print(ANS)