import java.io.*;
import java.util.*;

public class Main {

	final static long MOD = 1000000007L;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static ArrayList<int[]> list = new ArrayList<>();
	public static void main(String[] args) throws Exception {

		int N = nextInt();
		int[] A = new int[N+1];
		boolean[] flg = new boolean[N+1];
		for(int i=1;i<A.length;i++){
			A[i]=nextInt();
		}
		Arrays.fill(flg, true);

		int ans = 0;
		int idx=A[1];
		flg[1]=false;
		for(int i=1;i<=N;i++){
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		}

		if(flg[2]){
			ans=-1;
		}
		System.out.println(ans);
	}

	public static String[] toStringArray(String s) {
		String[] tmp = new String[s.length()];
		char[] c = s.toCharArray();
		for (int i = 0; i < tmp.length; i++) {
			tmp[i] = String.valueOf(c[i]);
		}
		return tmp;
	}

	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}


} import java.io.*; io.* java import java.util.*; util.* java public class Main {

	final static long MOD = 1000000007L;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static ArrayList<int[]> list = new ArrayList<>();
	public static void main(String[] args) throws Exception {

		int N = nextInt();
		int[] A = new int[N+1];
		boolean[] flg = new boolean[N+1];
		for(int i=1;i<A.length;i++){
			A[i]=nextInt();
		}
		Arrays.fill(flg, true);

		int ans = 0;
		int idx=A[1];
		flg[1]=false;
		for(int i=1;i<=N;i++){
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		}

		if(flg[2]){
			ans=-1;
		}
		System.out.println(ans);
	}

	public static String[] toStringArray(String s) {
		String[] tmp = new String[s.length()];
		char[] c = s.toCharArray();
		for (int i = 0; i < tmp.length; i++) {
			tmp[i] = String.valueOf(c[i]);
		}
		return tmp;
	}

	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}


} Main final static long MOD = 1000000007L; MOD 1000000007L public static String[] Ws = null; Ws null public static int wsIndx = 0; wsIndx 0 public static BufferedReader in = null; in null public static ArrayList<int[]> list = new ArrayList<>(); list new ArrayList<>() public static void main(String[] args) throws Exception {

		int N = nextInt();
		int[] A = new int[N+1];
		boolean[] flg = new boolean[N+1];
		for(int i=1;i<A.length;i++){
			A[i]=nextInt();
		}
		Arrays.fill(flg, true);

		int ans = 0;
		int idx=A[1];
		flg[1]=false;
		for(int i=1;i<=N;i++){
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		}

		if(flg[2]){
			ans=-1;
		}
		System.out.println(ans);
	} main {

		int N = nextInt();
		int[] A = new int[N+1];
		boolean[] flg = new boolean[N+1];
		for(int i=1;i<A.length;i++){
			A[i]=nextInt();
		}
		Arrays.fill(flg, true);

		int ans = 0;
		int idx=A[1];
		flg[1]=false;
		for(int i=1;i<=N;i++){
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		}

		if(flg[2]){
			ans=-1;
		}
		System.out.println(ans);
	} int N = nextInt(); N nextInt() nextInt int[] A = new int[N+1]; A new int[N+1] N+1 N 1 boolean[] flg = new boolean[N+1]; flg new boolean[N+1] N+1 N 1 for(int i=1;i<A.length;i++){
			A[i]=nextInt();
		} int i=1; int i=1; i 1 i<A.length i A.length A A.length i++ i++ i {
			A[i]=nextInt();
		} {
			A[i]=nextInt();
		} A[i]=nextInt() A[i] A i nextInt() nextInt Arrays.fill(flg, true) Arrays.fill Arrays flg true int ans = 0; ans 0 int idx=A[1]; idx A[1] A 1 flg[1]=false flg[1] flg 1 false for(int i=1;i<=N;i++){
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		} int i=1; int i=1; i 1 i<=N i N i++ i++ i {
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		} {
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		} if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			} flg[idx] flg idx {
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			} flg[idx]=false flg[idx] flg idx false ans++ ans if(idx==2){
					break;
				} idx==2 idx 2 {
					break;
				} break; idx=A[idx] idx A[idx] A idx {
				break;
			} break; if(flg[2]){
			ans=-1;
		} flg[2] flg 2 {
			ans=-1;
		} ans=-1 ans -1 1 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public static String[] toStringArray(String s) {
		String[] tmp = new String[s.length()];
		char[] c = s.toCharArray();
		for (int i = 0; i < tmp.length; i++) {
			tmp[i] = String.valueOf(c[i]);
		}
		return tmp;
	} toStringArray {
		String[] tmp = new String[s.length()];
		char[] c = s.toCharArray();
		for (int i = 0; i < tmp.length; i++) {
			tmp[i] = String.valueOf(c[i]);
		}
		return tmp;
	} String[] tmp = new String[s.length()]; tmp new String[s.length()] s.length() s.length s char[] c = s.toCharArray(); c s.toCharArray() s.toCharArray s for (int i = 0; i < tmp.length; i++) {
			tmp[i] = String.valueOf(c[i]);
		} int i = 0; int i = 0; i 0 i < tmp.length i tmp.length tmp tmp.length i++ i++ i {
			tmp[i] = String.valueOf(c[i]);
		} {
			tmp[i] = String.valueOf(c[i]);
		} tmp[i] = String.valueOf(c[i]) tmp[i] tmp i String.valueOf(c[i]) String.valueOf String c[i] c i return tmp; tmp String s s public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	} check {
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	} if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		} in == null in null {
			in = new BufferedReader(new InputStreamReader(System.in));
		} in = new BufferedReader(new InputStreamReader(System.in)) in new BufferedReader(new InputStreamReader(System.in)) if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		} Ws==null || Ws.length<=wsIndx Ws==null Ws null Ws.length<=wsIndx Ws.length Ws Ws.length wsIndx {
			Ws = in.readLine().split(" ");
			wsIndx=0;
		} Ws = in.readLine().split(" ") Ws in.readLine().split(" ") in.readLine().split in.readLine() in.readLine in " " wsIndx=0 wsIndx 0 public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	} nextInt {
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	} check() check return Integer.parseInt(Ws[wsIndx++]); Integer.parseInt(Ws[wsIndx++]) Integer.parseInt Integer Ws[wsIndx++] Ws wsIndx++ wsIndx public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	} nextLong {
		check();
		return Long.parseLong(Ws[wsIndx++]);
	} check() check return Long.parseLong(Ws[wsIndx++]); Long.parseLong(Ws[wsIndx++]) Long.parseLong Long Ws[wsIndx++] Ws wsIndx++ wsIndx public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	} nextString {
		check();
		return Ws[wsIndx++];
	} check() check return Ws[wsIndx++]; Ws[wsIndx++] Ws wsIndx++ wsIndx public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	} nextInts {
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	} check() check int[] tmp = new int[Ws.length]; tmp new int[Ws.length] Ws.length Ws Ws.length for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		} int i=0; int i=0; i 0 i<tmp.length i tmp.length tmp tmp.length i++ i++ i {
			tmp[i]=Integer.parseInt(Ws[i]);
		} {
			tmp[i]=Integer.parseInt(Ws[i]);
		} tmp[i]=Integer.parseInt(Ws[i]) tmp[i] tmp i Integer.parseInt(Ws[i]) Integer.parseInt Integer Ws[i] Ws i wsIndx=Ws.length wsIndx Ws.length Ws Ws.length return tmp; tmp public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	} nextLongs {
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	} check() check long[] tmp = new long[Ws.length]; tmp new long[Ws.length] Ws.length Ws Ws.length for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		} int i=0; int i=0; i 0 i<tmp.length i tmp.length tmp tmp.length i++ i++ i {
			tmp[i]=Long.parseLong(Ws[i]);
		} {
			tmp[i]=Long.parseLong(Ws[i]);
		} tmp[i]=Long.parseLong(Ws[i]) tmp[i] tmp i Long.parseLong(Ws[i]) Long.parseLong Long Ws[i] Ws i wsIndx=Ws.length wsIndx Ws.length Ws Ws.length return tmp; tmp public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	} nextStrings {
		check();
		wsIndx=Ws.length;
		return Ws;
	} check() check wsIndx=Ws.length wsIndx Ws.length Ws Ws.length return Ws; Ws public class Main {

	final static long MOD = 1000000007L;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static ArrayList<int[]> list = new ArrayList<>();
	public static void main(String[] args) throws Exception {

		int N = nextInt();
		int[] A = new int[N+1];
		boolean[] flg = new boolean[N+1];
		for(int i=1;i<A.length;i++){
			A[i]=nextInt();
		}
		Arrays.fill(flg, true);

		int ans = 0;
		int idx=A[1];
		flg[1]=false;
		for(int i=1;i<=N;i++){
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		}

		if(flg[2]){
			ans=-1;
		}
		System.out.println(ans);
	}

	public static String[] toStringArray(String s) {
		String[] tmp = new String[s.length()];
		char[] c = s.toCharArray();
		for (int i = 0; i < tmp.length; i++) {
			tmp[i] = String.valueOf(c[i]);
		}
		return tmp;
	}

	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}


} public class Main {

	final static long MOD = 1000000007L;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static ArrayList<int[]> list = new ArrayList<>();
	public static void main(String[] args) throws Exception {

		int N = nextInt();
		int[] A = new int[N+1];
		boolean[] flg = new boolean[N+1];
		for(int i=1;i<A.length;i++){
			A[i]=nextInt();
		}
		Arrays.fill(flg, true);

		int ans = 0;
		int idx=A[1];
		flg[1]=false;
		for(int i=1;i<=N;i++){
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		}

		if(flg[2]){
			ans=-1;
		}
		System.out.println(ans);
	}

	public static String[] toStringArray(String s) {
		String[] tmp = new String[s.length()];
		char[] c = s.toCharArray();
		for (int i = 0; i < tmp.length; i++) {
			tmp[i] = String.valueOf(c[i]);
		}
		return tmp;
	}

	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}


} Main
import java.io.*;
import java.util.*;

public class Main {

	final static long MOD = 1000000007L;
	public static String[] Ws = null;
	public static int wsIndx = 0;
	public static BufferedReader in = null;
	public static ArrayList<int[]> list = new ArrayList<>();
	public static void main(String[] args) throws Exception {

		int N = nextInt();
		int[] A = new int[N+1];
		boolean[] flg = new boolean[N+1];
		for(int i=1;i<A.length;i++){
			A[i]=nextInt();
		}
		Arrays.fill(flg, true);

		int ans = 0;
		int idx=A[1];
		flg[1]=false;
		for(int i=1;i<=N;i++){
			if(flg[idx]){
				flg[idx]=false;
				ans++;
				if(idx==2){
					break;
				}
				idx=A[idx];

			}else{
				break;
			}
		}

		if(flg[2]){
			ans=-1;
		}
		System.out.println(ans);
	}

	public static String[] toStringArray(String s) {
		String[] tmp = new String[s.length()];
		char[] c = s.toCharArray();
		for (int i = 0; i < tmp.length; i++) {
			tmp[i] = String.valueOf(c[i]);
		}
		return tmp;
	}

	public static void check() throws Exception{
		if(in == null){
			in = new BufferedReader(new InputStreamReader(System.in));
		}
		if(Ws==null || Ws.length<=wsIndx){
			Ws = in.readLine().split(" ");
			wsIndx=0;
		}
	}
	public static int nextInt()throws Exception{
		check();
		return Integer.parseInt(Ws[wsIndx++]);
	}

	public static long nextLong()throws Exception{
		check();
		return Long.parseLong(Ws[wsIndx++]);
	}

	public static String nextString()throws Exception{
		check();
		return Ws[wsIndx++];
	}

	public static int[] nextInts()throws Exception{
		check();
		int[] tmp = new int[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Integer.parseInt(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static long[] nextLongs()throws Exception{
		check();
		long[] tmp = new long[Ws.length];
		for(int i=0;i<tmp.length;i++){
			tmp[i]=Long.parseLong(Ws[i]);
		}
		wsIndx=Ws.length;
		return tmp;
	}

	public static String[] nextStrings()throws Exception{
		check();
		wsIndx=Ws.length;
		return Ws;
	}


}
