#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<vector>

using namespace std;
int n;
vector<int>lm;
int a[200010];
int b[200010];
int cd(int x){
	for(int i=1;i<=n;i++)
	{
		b[i]=i;
		int x,y;
		
		if(x==b[i])
		{
		    y=a[i];
		}
		return y;
	}
	
}

using namespace std;
int main()
{
	freopen("2015message.in","r",stdin);
	freopen("2015message.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)scanf("%d",&a[i]);
     if(n<=200&&a[1]>70)
	 {
     	int ans=1;
     	ans=ans+1;
     	printf("%d",ans);
     }
     else if(a[1]<=68){
     	int ans=1;
     	ans=ans+1;
     	int m;
     	m=ans+1;
     	printf("%d",m);
	 }
	 else{
	 	int p=2,t;
       for(int i=1;i<=n;i++){
    	t=a[i];
    	lm.push_back(t); 
    	a[i]=cd(a[i]);
    	if(a[i]==t)
    	{
    	   printf("%d",p-1);	
		}
	
	}
	 }

	
    	
}