import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int a[];
		a = new int [n + 1];

		for (int i = 1; i <= n; i++){
			a[i] = sc.nextInt();
		}

		int idx = 1;
		int cnt = 0;
		Set<Integer> set = new HashSet<Integer>();
		set.add(idx);
		while (true){

			idx = a[idx];
			cnt++;

			if (idx == 2){
				break;
			}
			if (set.contains(idx)){
				cnt = -1;
				break;
			}
			set.add(idx);
		}


		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