import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] al = new int[n];
        for(int i = 0; i < n; i++){
            al[i] = sc.nextInt()-1;
        }
        int ans = 0;
        int ind = 0;
        HashSet<Integer> hs = new HashSet<Integer>();
        while(true){
            if(hs.contains(ind)){
                System.out.println(-1);
                break;
            }else if(ind == 1){
                System.out.println(ans);
                break;
            }else{
                ans++;
                hs.add(ind);
                ind = al[ind];
            }
        }
    }
}
/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