import java.util.Arrays;
import java.util.Scanner;
class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] P = new int[N];
		Arrays.setAll(P,i->sc.nextInt()-1);
		UnionFind uf = new UnionFind(N);
		int ans = 0;
		for(int i=0;i<N;i++){
			if(uf.size(i)>1)
				continue;
			int p = i;
			while(uf.unite(p,P[p]))
				p = P[p];
			ans += uf.size(i)-1;
		}
		System.out.println(ans);
	}
}
class UnionFind{
	int[] size,par;
	UnionFind(int N){
		size = new int[N];
		par = new int[N];
		Arrays.fill(size,1);
		Arrays.fill(par,-1);
	}
	boolean unite(int x,int y){
		int rootX = root(x);
		int rootY = root(y);
		if(rootX==rootY)
			return false;
		if(size[y]<size[x]){
			int temp = rootX;
			rootX = rootY;
			rootY = rootX;
		}
		par[rootY] = rootX;
		size[rootX] += size[rootY];
		return true;
	}
	int size(int x){
		return size[root(x)];
	}
	int root(int x){
		if(par[x]==-1)
			return x;
		return par[x] = root(par[x]);
	}
}