#include<bits/stdc++.h>
#define int long long
using namespace std;
vector<int> ljb[1000005];
int n;
int dfn[1000005],low[1000005];
int now;
bool in[1000005];
int belone[1000005];
stack<int> stk;
int cnt;
int rd[1000005];
int ans;
void tarjan(int cur){
	dfn[cur]=low[cur]=++now;
	stk.push(cur);in[cur]=true;
	for(int i=0;i<ljb[cur].size();i++){
		int v=ljb[cur][i];
		if(!dfn[v]){
			tarjan(v);
			low[cur]=min(low[cur],low[v]);
		}else{
			if(in[v]){
				low[cur]=min(low[cur],dfn[v]);
			}
		}
	}
	if(dfn[cur]==low[cur]){
		cnt++;
		while(stk.top()!=cur){
			int tmp=stk.top();
			stk.pop();
			belone[tmp]=cnt;
			in[tmp]=false;
		}
		in[cur]=false;
		belone[cur]=cnt;
		stk.pop();
	}
	return;
}
signed main(){
	scanf("%lld",&n);
	for(int i=1;i<=n;i++){
		int x;
		scanf("%lld",&x);
		ljb[i].push_back(x);
	}
	for(int i=1;i<=n;i++){
		if(!dfn[i])tarjan(i);
	}
	for(int i=1;i<=n;i++){
		for(int j=0;j<ljb[i].size();j++){
			int v=ljb[i][j];
			int fx=belone[i];
			int fy=belone[v];
			if(fx==fy){
				continue;
			}
			rd[fy]++;
		}
	}
	for(int i=1;i<=cnt;i++){
		if(!rd[i]){
			ans++;
		}
	}
	printf("%lld",ans);
	return 0;
}
/*
4
2
1
2
4
*/

/ll/ll

机房同学都没看出哪有问题