import java.io.InputStream;
import java.util.Scanner;

public class Main {
	static Scanner sc;

	public static void main(String[] args) throws Exception {
		//InputStream in = new FileInputStream("src/input.txt");
		InputStream in = System.in;

		sc = new Scanner(in);
		
		int n = sc.nextInt();
		
		int[] a = new int[n];
		
		for(int i = 0; i < n; i++){
			a[i] = sc.nextInt() - 1;
		}
		
		int answer = 0;
		int nowPoint = 0;
		
		while(nowPoint + 1 != 2){
			int prePoint = nowPoint;
			nowPoint = a[nowPoint] ;
			a[prePoint] = -1;
			answer++;
			//System.out.println("ans " + answer);
			if(nowPoint == -1){
				answer = -1;
				break;
				//System.out.println("out");
			}
		}
		
		System.out.println(answer);

	}
}
/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