import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {
    static int[] g;

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        g = new int[n + 1];
        for (int i = 1; i <= n; i++) {
            int a = sc.nextInt();
            g[i] = a;
        }
        Set<Integer> s = new HashSet<>();
        int current = 1;
        while (!s.contains(current)) {
            s.add(current);
            if (!s.contains(g[current])) {
                if (g[current] == 2) {
                    s.add(2);
                } else {
                    current = g[current];
                }
            }
        }

        if (s.contains(2)) {
            System.out.println(s.size() - 1);
        } else {
            System.out.println(-1);
        }
    }
}
/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