#include <iostream>
#include <cstdio>
#include <cstring>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <cmath>
#include <queue>
#include <stack>
#include <map>
#include <cstdlib>
#include <cctype>
#define ll long long
#define sll static long long
#define db double
#define sint static int
#define lint inline int
#define lb inline bool
#define lll inline long long
using namespace std;
ll n, fa[10001000], cnt = 0, ans = -0x3f3f3f3f3f3f3f3f;
ll getf(ll x) {
	cnt++;
	if (x == fa[x]) return x;
	else return getf(fa[x]);
}
void Merge(int x, int y) {
	int fx = getf(x);
	int fy = getf(y);
	if (fx != fy)
		fa[fy] = fx;
}
int main() {
	cin >> n;
	for (int i = 1; i <= n; i++) fa[i] = i;
	for (int i = 1; i <= n; i++) {
		cnt = 0;
		int x;
		cin >> x;
		if (getf(x) == i) {
			ans = min(ans, cnt);
		} else {
			Merge(x, i);
		}
	}
	cout << ans;
	return 0;
}