1 #include <bits/stdc++.h>
2 #define _for(i,a,b) for(int i = (a);i < b;i ++)
3 #define _rep(i,a,b) for(int i = (a);i > b;i --)
4 #define INF 0x3f3f3f3f
5 #define pb push_back
6 typedef long long ll;
7 using namespace std;
8 inline ll read()
9 {
10 ll ans = 0;
11 char ch = getchar(), last = ' ';
12 while(!isdigit(ch)) last = ch, ch = getchar();
13 while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
14 if(last == '-') ans = -ans;
15 return ans;
16 }
17 inline void write(ll x)
18 {
19 if(x < 0) x = -x, putchar('-');
20 if(x >= 10) write(x / 10);
21 putchar(x % 10 + '0');
22 }
23
24 int e[200003];
25 int state[200003];
26 int m[200003];
27 int vis[200003];
28 int st;
29 int N;
30 int rnt = 0x3f3f3f3f;
31 void dfs(int nw)
32 {
33 if(vis[nw])
34 return ;
35 vis[nw] = 1;
36 if(state[e[nw]]==-1)
37 {
38 rnt = min(rnt,m[nw]-m[e[nw]]+1);
39 return ;
40 }
41 state[nw] = -1;
42 m[e[nw]] = m[nw]+1;
43 dfs(e[nw]);
44 state[nw] = 0;
45 }
46 int main()
47 {
48 // freopen("testdata.txt","w+",stdin);
49 N = read();
50 _for(i,1,N+1)
51 e[i] = read();
52 _for(i,1,N+1)
53 {
54 if(!vis[i])
55 dfs(i);
56 }
57 write(rnt);
58 return 0;
59 }
