import java.util.Scanner;
public class Main {

	public static void main(String[] args) {
		try{
			Scanner sc = new Scanner(System.in);
			int N = sc.nextInt();
			int[] a = new int[N+1];
			for(int i = 1; i < N+1; i++){
				a[i] = sc.nextInt();
			}
			int result = 0;
			int i = 1;
			while(a[i] != 0){
				if(i == 2){
					a[i] = 0;
					break;
				}
				result ++;
				int temp = i;
				i = a[i];
				a[temp] = 0;
			}
			if(a[2] != 0){
				result = -1;
			}
			System.out.println(result);
			
		}catch(Exception e){
			e.printStackTrace();
		}
	}
}
/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