#include<iostream>

#include<cstdio>

#include<cstring>

#define maxn 200009

using namespace std;

int top,n,sumedge,sumclr,tim,ans;

int head[maxn],Stack[maxn],instack[maxn],low[maxn],dfn[maxn],cnt[maxn];

struct Edge{

    int x,y,nxt;

    Edge(int x=,int y=,int nxt=):

        x(x),y(y),nxt(nxt){}

}edge[maxn];

void add(int x,int y){

    edge[++sumedge]=Edge(x,y,head[x]);

    head[x]=sumedge;

}

void Tarjian(int x){

    Stack[++top]=x;instack[x]=true;

    low[x]=dfn[x]=++tim;

    for(int i=head[x];i;i=edge[i].nxt){

        int v=edge[i].y;

        if(instack[v])low[x]=min(low[x],dfn[v]);

        else if(!dfn[v]){

            Tarjian(v);

            low[x]=min(low[x],low[v]);

        }

    }

    if(low[x]==dfn[x]){

        ++sumclr;

        while(Stack[top+]!=x){

            cnt[sumclr]++;

            instack[Stack[top]]=false;

            top--;

        }

    }

}

int main(){

    scanf("%d",&n);ans=n+;

    for(int i=;i<=n;i++){

        int x;

        scanf("%d",&x);

        add(i,x);

    }

    for(int i=;i<=n;i++)if(!dfn[i])Tarjian(i);

    for(int i=;i<=sumclr;i++)if(cnt[i]!=)ans=min(ans,cnt[i]);

    printf("%d\n",ans==n+?:ans);

    return ;

}

#include<iostream>

#include<algorithm>

#include<cstdio>

#define maxn 200001

using namespace std;

int n,ans,tim,m;

struct Node{

    int fa,tag,v,vis;

}g[maxn];

void dfs(int x,int fa){

    g[x].tag=++tim;g[x].fa=fa;

    if(!g[g[x].v].fa)dfs(g[x].v,fa);

    else if(g[g[x].v].fa==fa)

    ans=min(ans,tim-g[g[x].v].tag+);

}

int main(){

    scanf("%d",&n);ans=n+;

    for(int i=;i<=n;i++)scanf("%d",&g[i].v);

    for(int i=;i<=n;i++)

     if(!g[i].fa)dfs(i,i);

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

    return ;

}