import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		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();
		}
		sc.close();

		int prev = 0;
		int cur = 1;
		int count = 0;

		while(cur != 2 && cur != 0){
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		}
		if(cur == 2){
			System.out.println(count);
		}
		else{
			System.out.println(-1);
		}
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {

		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();
		}
		sc.close();

		int prev = 0;
		int cur = 1;
		int count = 0;

		while(cur != 2 && cur != 0){
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		}
		if(cur == 2){
			System.out.println(count);
		}
		else{
			System.out.println(-1);
		}
	}

} Main public static void main(String[] args) {

		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();
		}
		sc.close();

		int prev = 0;
		int cur = 1;
		int count = 0;

		while(cur != 2 && cur != 0){
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		}
		if(cur == 2){
			System.out.println(count);
		}
		else{
			System.out.println(-1);
		}
	} main {

		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();
		}
		sc.close();

		int prev = 0;
		int cur = 1;
		int count = 0;

		while(cur != 2 && cur != 0){
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		}
		if(cur == 2){
			System.out.println(count);
		}
		else{
			System.out.println(-1);
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[] a = new int[N+1]; a new int[N+1] N+1 N 1 for(int i = 1; i < N+1; i++){
			a[i] = sc.nextInt();
		} int i = 1; int i = 1; i 1 i < N+1 i N+1 N 1 i++ i++ i {
			a[i] = sc.nextInt();
		} {
			a[i] = sc.nextInt();
		} a[i] = sc.nextInt() a[i] a i sc.nextInt() sc.nextInt sc sc.close() sc.close sc int prev = 0; prev 0 int cur = 1; cur 1 int count = 0; count 0 while(cur != 2 && cur != 0){
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		} cur != 2 && cur != 0 cur != 2 cur 2 cur != 0 cur 0 {
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		} prev = cur prev cur cur = a[cur] cur a[cur] a cur a[prev] = 0 a[prev] a prev 0 count++ count if(cur == 2){
			System.out.println(count);
		}
		else{
			System.out.println(-1);
		} cur == 2 cur 2 {
			System.out.println(count);
		} System.out.println(count) System.out.println System.out System System.out count {
			System.out.println(-1);
		} System.out.println(-1) System.out.println System.out System System.out -1 1 String[] args args public class Main {

	public static void main(String[] args) {

		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();
		}
		sc.close();

		int prev = 0;
		int cur = 1;
		int count = 0;

		while(cur != 2 && cur != 0){
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		}
		if(cur == 2){
			System.out.println(count);
		}
		else{
			System.out.println(-1);
		}
	}

} public class Main {

	public static void main(String[] args) {

		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();
		}
		sc.close();

		int prev = 0;
		int cur = 1;
		int count = 0;

		while(cur != 2 && cur != 0){
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		}
		if(cur == 2){
			System.out.println(count);
		}
		else{
			System.out.println(-1);
		}
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		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();
		}
		sc.close();

		int prev = 0;
		int cur = 1;
		int count = 0;

		while(cur != 2 && cur != 0){
			prev = cur;
			cur = a[cur];
			a[prev] = 0;
			count++;
		}
		if(cur == 2){
			System.out.println(count);
		}
		else{
			System.out.println(-1);
		}
	}

}
