#include<iostream>

 #include<cstdio>

 #include<queue>

 #include<algorithm>

 #include<cmath>

 #include<ctime>

 #include<set>

 #include<map>

 #include<stack>

 #include<cstring>

 #define inf 2147483647

 #define For(i,a,b) for(register int i=a;i<=b;i++)

 #define p(a) putchar(a)

 #define g() getchar()

 //by war

 //2017.11.5

 using namespace std;

 int n;

 bool vis[];

 int x;

 int ans;

 int d[];

 int t[];

 struct node

 {

     int n;

     node *next;

 }*e[];

 void in(int &x)

 {

     int y=;

     char c=g();x=;

     while(c<''||c>'')

     {

     if(c=='-')

     y=-;

     c=g();

     }

     while(c<=''&&c>='')x=(x<<)+(x<<)+c-'',c=g();

     x*=y;

 }

 void o(int x)

 {

     if(x<)

     {

         p('-');

         x=-x;

     }

     if(x>)o(x/);

     p(x%+'');

 }

 void push(int x,int y)

 {

     node *p;

     p=new node();

     p->n=y;

     if(e[x]==NULL)

     e[x]=p;

     else

     {

         p->next=e[x]->next;

         e[x]->next=p;

     }

 }

 void dfs(int now,int dis,int Time)

 {

     d[now]=dis;

     vis[now]=true;

     t[now]=Time;

     for(node *i=e[now];i!=NULL;i=i->next)

     if(vis[i->n])

     {

     if(t[now]==t[i->n])

     ans=min(ans,d[now]-d[i->n]+);

     }

     else

     dfs(i->n,dis+,Time);

 }

 int main()

 {

     in(n);

     For(i,,n)

     {

         in(x);

         push(i,x);

     }

     ans=inf;

     For(i,,n)

     {

         if(!vis[i])

         {

         t[i]=i;

         dfs(i,,i);

         }

     }

     o(ans);

      return ;

 }