#include<cstdio>

 #include<vector>

 using namespace std;

 #define ll long long

 #define FILE "dealing"

 #define up(i,j,n) for(int i=j;i<=n;i++)

 #define db long double

 #define pii pair<int,int>

 #define pb push_back

 #define mem(a,L) memset(a,0,sizeof(int)*(L+1))

 template<class T> inline bool cmin(T& a,T b){return a>b?a=b,true:false;}

 template<class T> inline bool cmax(T& a,T b){return a<b?a=b,true:false;}

 template<class T> inline T squ(T a){return a*a;}

 const ll maxn=+,inf=1e9+,limit=1e7;

 int read(){

     int x=,f=,ch=getchar();

     while(ch<''||ch>''){if(ch=='-')f=-;ch=getchar();}

     while(ch>=''&&ch<='')x=(x<<)+(x<<)+ch-'',ch=getchar();

     return x*f;

 }

 int n;

 vector<int> t[maxn];

 int f[maxn],g[maxn],to[maxn];

 int vis[maxn];

 int rt,rt2,q[maxn],top=;

 void dfs(int x){

     q[++top]=x;

     vis[x]=;

     if(!vis[to[x]])dfs(to[x]);

     else {

         rt=x;

         rt2=to[x];

     }

 }

 void dfs2(int x){

     vis[x]=;

     for(int i=;i<t[x].size();i++)

         if(!vis[t[x][i]])dfs2(t[x][i]);

     if(!vis[to[x]])dfs2(to[x]);

 }

 //f[x] 选 g[x] 不选

 int flag=;

 void dfs1(int x){//选rt

     f[x]=,g[x]=;int Max=-inf;

     for(int i=;i<t[x].size();i++){

         int y=t[x][i];if((x==rt2&&y==rt))continue;

         dfs1(y);

         f[x]+=f[y];

         g[x]+=f[y];

         cmax(Max,g[y]-f[y]);

     }

     f[x]+=Max;

     if(x==rt2&&flag)f[x]-=Max;

     cmax(f[x],);

 }

 int main(){

     freopen(FILE".in","r",stdin);

     freopen(FILE".out","w",stdout);

     n=read();

     up(i,,n){

         to[i]=read();

         t[to[i]].push_back(i);

     }

     int ans=;

     up(i,,n){

         if(vis[i])continue;

         top=;dfs(i);

         while(top)vis[q[top--]]=;

         dfs2(i);

         int Ans=;

         flag=;

         dfs1(rt);

         cmax(Ans,g[rt]);

         flag=;

         dfs1(rt);

         cmax(Ans,f[rt]);

         ans+=Ans;

     }

     printf("%d\n",ans);

     return ;

 }