
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int N = scan.nextInt();
		int sum = 0;
		int index = 0;
		int tmpIndex = 0;
		int[] a = new int[N];
		for(int i = 0; i < N; i++) {
			a[i] = scan.nextInt();
		}
		while(true) {
			tmpIndex = index;
			index = a[index] - 1;
			a[tmpIndex] = 0;
			sum++;
			if(index == -1) {
				sum = -1;
				break;
			} else if(index == 1) {
				break;
			}
		}
		System.out.println(sum);
		scan.close();
	}

}

/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