import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] input = new int[N + 1];
		for (int i = 1; i <= N; i++) {
			int tmp = sc.nextInt();
			input[i] = tmp;
		}
		int index = 1;
		int res = 0;
		while (index != 2) {
			if (input[index] == 0) {
				System.out.println(-1);
				System.exit(0);
			}
			int tmp = input[index];
			input[index] = 0;
			index = tmp;
			res++;
		}
		System.out.println(res);

	}
}

/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