import java.util.*;

public class Main {

	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] num = new int[N+1];
		for (int i = 1; i <= N; i++) {
			num[i] = sc.nextInt();
		}
		int number = 1;
		int count = 0;
		boolean key = false;
		for (int i = 1; i <= N; i++) {
			int tmp = num[number];
			if (tmp == -1) {
				System.out.println(-1);
				System.exit(0);
			}
			num[number] = -1;
			number = tmp;
			count++;
			if (number == 2) {
				key = true;
				break;
			}
		}
		System.out.println(true?count:-1);
	}
}
/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