import java.util.*;
class Main {
    public static void main(String[] args) {
	Scanner sc = new Scanner(System.in);
	HashSet<Integer> set = new HashSet<Integer>();
	int N = Integer.parseInt(sc.next());
	int[] a = new int[N+1];
	for(int i = 1; i<=N; i++) {
	    a[i] = Integer.parseInt(sc.next());
	}
	int next = 1;
	int cnt = 0;
	for(int i = 0; i<N; i++) {
	    if(next == 2) {
		System.out.println(cnt);
		return;
	    }
	    if(set.contains(next)) {
		System.out.println(-1);
		return;
	    }
	    set.add(next);
	    next = a[next];
	    cnt++;
	}
	System.out.println(cnt);
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz