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

class Main {
    public static void main(String args[]) throws IOException {
        Scan sc = new Scan();
        int n = sc.scanInt();
        int[] arr = new int[n+1];
        for(int i = 1; i <= n; ++i)
            arr[i] = sc.scanInt();
        int now = arr[1];
        int id = 1;
        int ct = 0;
        while(true){
            arr[id] = 0;
            id = now;
            now = arr[id];
            ++ct;
            if(id == 2 || now == 0)
                break;
        }
        if(id == 2)
            System.out.println(ct);
        else
            System.out.println(-1);
    }
}

class Scan {
    private byte[] buf=new byte[1024];
    private int index;
    private InputStream in;
    private int total;
    public Scan()
    {
        in=System.in;
    }
    public int scan()throws IOException
    {
        if(total<0)
        throw new InputMismatchException();
        if(index>=total)
        {
            index=0;
            total=in.read(buf);
            if(total<=0)
            return -1;
        }
        return buf[index++];
    }
    public int scanInt()throws IOException
    {
        int integer=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n))
        {
            if(n>='0'&&n<='9')
            {
                integer*=10;
                integer+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        return neg*integer;
    }
    public double scanDouble()throws IOException
    {
        double doub=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n)&&n!='.')
        {
            if(n>='0'&&n<='9')
            {
                doub*=10;
                doub+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        if(n=='.')
        {
            n=scan();
            double temp=1;
            while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            }
        }
        return doub*neg;
    }
    public String scanString()throws IOException
    {
        StringBuilder sb=new StringBuilder();
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        while(!isWhiteSpace(n))
        {
            sb.append((char)n);
            n=scan();
        }
        return sb.toString();
    }
    private boolean isWhiteSpace(int n)
    {
        if(n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1)
        return true;
        return false;
    }
} import java.io.*; io.* java import java.util.*; util.* java class Main {
    public static void main(String args[]) throws IOException {
        Scan sc = new Scan();
        int n = sc.scanInt();
        int[] arr = new int[n+1];
        for(int i = 1; i <= n; ++i)
            arr[i] = sc.scanInt();
        int now = arr[1];
        int id = 1;
        int ct = 0;
        while(true){
            arr[id] = 0;
            id = now;
            now = arr[id];
            ++ct;
            if(id == 2 || now == 0)
                break;
        }
        if(id == 2)
            System.out.println(ct);
        else
            System.out.println(-1);
    }
} Main public static void main(String args[]) throws IOException {
        Scan sc = new Scan();
        int n = sc.scanInt();
        int[] arr = new int[n+1];
        for(int i = 1; i <= n; ++i)
            arr[i] = sc.scanInt();
        int now = arr[1];
        int id = 1;
        int ct = 0;
        while(true){
            arr[id] = 0;
            id = now;
            now = arr[id];
            ++ct;
            if(id == 2 || now == 0)
                break;
        }
        if(id == 2)
            System.out.println(ct);
        else
            System.out.println(-1);
    } main {
        Scan sc = new Scan();
        int n = sc.scanInt();
        int[] arr = new int[n+1];
        for(int i = 1; i <= n; ++i)
            arr[i] = sc.scanInt();
        int now = arr[1];
        int id = 1;
        int ct = 0;
        while(true){
            arr[id] = 0;
            id = now;
            now = arr[id];
            ++ct;
            if(id == 2 || now == 0)
                break;
        }
        if(id == 2)
            System.out.println(ct);
        else
            System.out.println(-1);
    } Scan sc = new Scan(); sc new Scan() int n = sc.scanInt(); n sc.scanInt() sc.scanInt sc int[] arr = new int[n+1]; arr new int[n+1] n+1 n 1 for(int i = 1; i <= n; ++i)
            arr[i] = sc.scanInt(); int i = 1; int i = 1; i 1 i <= n i n ++i ++i i arr[i] = sc.scanInt(); arr[i] = sc.scanInt() arr[i] arr i sc.scanInt() sc.scanInt sc int now = arr[1]; now arr[1] arr 1 int id = 1; id 1 int ct = 0; ct 0 while(true){
            arr[id] = 0;
            id = now;
            now = arr[id];
            ++ct;
            if(id == 2 || now == 0)
                break;
        } true {
            arr[id] = 0;
            id = now;
            now = arr[id];
            ++ct;
            if(id == 2 || now == 0)
                break;
        } arr[id] = 0 arr[id] arr id 0 id = now id now now = arr[id] now arr[id] arr id ++ct ct if(id == 2 || now == 0)
                break; id == 2 || now == 0 id == 2 id 2 now == 0 now 0 break; if(id == 2)
            System.out.println(ct);
        else
            System.out.println(-1); id == 2 id 2 System.out.println(ct) System.out.println System.out System System.out ct System.out.println(-1) System.out.println System.out System System.out -1 1 String args[] args class Scan {
    private byte[] buf=new byte[1024];
    private int index;
    private InputStream in;
    private int total;
    public Scan()
    {
        in=System.in;
    }
    public int scan()throws IOException
    {
        if(total<0)
        throw new InputMismatchException();
        if(index>=total)
        {
            index=0;
            total=in.read(buf);
            if(total<=0)
            return -1;
        }
        return buf[index++];
    }
    public int scanInt()throws IOException
    {
        int integer=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n))
        {
            if(n>='0'&&n<='9')
            {
                integer*=10;
                integer+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        return neg*integer;
    }
    public double scanDouble()throws IOException
    {
        double doub=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n)&&n!='.')
        {
            if(n>='0'&&n<='9')
            {
                doub*=10;
                doub+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        if(n=='.')
        {
            n=scan();
            double temp=1;
            while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            }
        }
        return doub*neg;
    }
    public String scanString()throws IOException
    {
        StringBuilder sb=new StringBuilder();
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        while(!isWhiteSpace(n))
        {
            sb.append((char)n);
            n=scan();
        }
        return sb.toString();
    }
    private boolean isWhiteSpace(int n)
    {
        if(n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1)
        return true;
        return false;
    }
} Scan private byte[] buf=new byte[1024]; buf new byte[1024] 1024 private int index; index private InputStream in; in private int total; total public Scan()
    {
        in=System.in;
    } Scan {
        in=System.in;
    } in=System.in in System.in System System.in public int scan()throws IOException
    {
        if(total<0)
        throw new InputMismatchException();
        if(index>=total)
        {
            index=0;
            total=in.read(buf);
            if(total<=0)
            return -1;
        }
        return buf[index++];
    } scan {
        if(total<0)
        throw new InputMismatchException();
        if(index>=total)
        {
            index=0;
            total=in.read(buf);
            if(total<=0)
            return -1;
        }
        return buf[index++];
    } if(total<0)
        throw new InputMismatchException(); total<0 total 0 throw new InputMismatchException(); new InputMismatchException() if(index>=total)
        {
            index=0;
            total=in.read(buf);
            if(total<=0)
            return -1;
        } index>=total index total {
            index=0;
            total=in.read(buf);
            if(total<=0)
            return -1;
        } index=0 index 0 total=in.read(buf) total in.read(buf) in.read in buf if(total<=0)
            return -1; total<=0 total 0 return -1; -1 1 return buf[index++]; buf[index++] buf index++ index public int scanInt()throws IOException
    {
        int integer=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n))
        {
            if(n>='0'&&n<='9')
            {
                integer*=10;
                integer+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        return neg*integer;
    } scanInt {
        int integer=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n))
        {
            if(n>='0'&&n<='9')
            {
                integer*=10;
                integer+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        return neg*integer;
    } int integer=0; integer 0 int n=scan(); n scan() scan while(isWhiteSpace(n))
        n=scan(); isWhiteSpace(n) isWhiteSpace n n=scan() n scan() scan int neg=1; neg 1 if(n=='-')
        {
            neg=-1;
            n=scan();
        } n=='-' n '-' {
            neg=-1;
            n=scan();
        } neg=-1 neg -1 1 n=scan() n scan() scan while(!isWhiteSpace(n))
        {
            if(n>='0'&&n<='9')
            {
                integer*=10;
                integer+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        } !isWhiteSpace(n) isWhiteSpace(n) isWhiteSpace n {
            if(n>='0'&&n<='9')
            {
                integer*=10;
                integer+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        } if(n>='0'&&n<='9')
            {
                integer*=10;
                integer+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException(); n>='0'&&n<='9' n>='0' n '0' n<='9' n '9' {
                integer*=10;
                integer+=n-'0';
                n=scan();
            } integer*=10 integer 10 integer+=n-'0' integer n-'0' n '0' n=scan() n scan() scan throw new InputMismatchException(); new InputMismatchException() return neg*integer; neg*integer neg integer public double scanDouble()throws IOException
    {
        double doub=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n)&&n!='.')
        {
            if(n>='0'&&n<='9')
            {
                doub*=10;
                doub+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        if(n=='.')
        {
            n=scan();
            double temp=1;
            while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            }
        }
        return doub*neg;
    } scanDouble {
        double doub=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n)&&n!='.')
        {
            if(n>='0'&&n<='9')
            {
                doub*=10;
                doub+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        if(n=='.')
        {
            n=scan();
            double temp=1;
            while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            }
        }
        return doub*neg;
    } double doub=0; doub 0 int n=scan(); n scan() scan while(isWhiteSpace(n))
        n=scan(); isWhiteSpace(n) isWhiteSpace n n=scan() n scan() scan int neg=1; neg 1 if(n=='-')
        {
            neg=-1;
            n=scan();
        } n=='-' n '-' {
            neg=-1;
            n=scan();
        } neg=-1 neg -1 1 n=scan() n scan() scan while(!isWhiteSpace(n)&&n!='.')
        {
            if(n>='0'&&n<='9')
            {
                doub*=10;
                doub+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        } !isWhiteSpace(n)&&n!='.' !isWhiteSpace(n) isWhiteSpace(n) isWhiteSpace n n!='.' n '.' {
            if(n>='0'&&n<='9')
            {
                doub*=10;
                doub+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        } if(n>='0'&&n<='9')
            {
                doub*=10;
                doub+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException(); n>='0'&&n<='9' n>='0' n '0' n<='9' n '9' {
                doub*=10;
                doub+=n-'0';
                n=scan();
            } doub*=10 doub 10 doub+=n-'0' doub n-'0' n '0' n=scan() n scan() scan throw new InputMismatchException(); new InputMismatchException() if(n=='.')
        {
            n=scan();
            double temp=1;
            while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            }
        } n=='.' n '.' {
            n=scan();
            double temp=1;
            while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            }
        } n=scan() n scan() scan double temp=1; temp 1 while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            } !isWhiteSpace(n) isWhiteSpace(n) isWhiteSpace n {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            } if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException(); n>='0'&&n<='9' n>='0' n '0' n<='9' n '9' {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                } temp/=10 temp 10 doub+=(n-'0')*temp doub (n-'0')*temp (n-'0') n '0' temp n=scan() n scan() scan throw new InputMismatchException(); new InputMismatchException() return doub*neg; doub*neg doub neg public String scanString()throws IOException
    {
        StringBuilder sb=new StringBuilder();
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        while(!isWhiteSpace(n))
        {
            sb.append((char)n);
            n=scan();
        }
        return sb.toString();
    } scanString {
        StringBuilder sb=new StringBuilder();
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        while(!isWhiteSpace(n))
        {
            sb.append((char)n);
            n=scan();
        }
        return sb.toString();
    } StringBuilder sb=new StringBuilder(); sb new StringBuilder() int n=scan(); n scan() scan while(isWhiteSpace(n))
        n=scan(); isWhiteSpace(n) isWhiteSpace n n=scan() n scan() scan while(!isWhiteSpace(n))
        {
            sb.append((char)n);
            n=scan();
        } !isWhiteSpace(n) isWhiteSpace(n) isWhiteSpace n {
            sb.append((char)n);
            n=scan();
        } sb.append((char)n) sb.append sb (char)n n=scan() n scan() scan return sb.toString(); sb.toString() sb.toString sb private boolean isWhiteSpace(int n)
    {
        if(n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1)
        return true;
        return false;
    } isWhiteSpace {
        if(n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1)
        return true;
        return false;
    } if(n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1)
        return true; n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1 n=='\t' n=='\r' n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1 n==' ' n ' ' n=='\n' n '\n' n=='\r' n '\r' n=='\t' n '\t' n==-1 n -1 1 return true; true return false; false int n n
import java.io.*;
import java.util.*;

class Main {
    public static void main(String args[]) throws IOException {
        Scan sc = new Scan();
        int n = sc.scanInt();
        int[] arr = new int[n+1];
        for(int i = 1; i <= n; ++i)
            arr[i] = sc.scanInt();
        int now = arr[1];
        int id = 1;
        int ct = 0;
        while(true){
            arr[id] = 0;
            id = now;
            now = arr[id];
            ++ct;
            if(id == 2 || now == 0)
                break;
        }
        if(id == 2)
            System.out.println(ct);
        else
            System.out.println(-1);
    }
}

class Scan {
    private byte[] buf=new byte[1024];
    private int index;
    private InputStream in;
    private int total;
    public Scan()
    {
        in=System.in;
    }
    public int scan()throws IOException
    {
        if(total<0)
        throw new InputMismatchException();
        if(index>=total)
        {
            index=0;
            total=in.read(buf);
            if(total<=0)
            return -1;
        }
        return buf[index++];
    }
    public int scanInt()throws IOException
    {
        int integer=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n))
        {
            if(n>='0'&&n<='9')
            {
                integer*=10;
                integer+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        return neg*integer;
    }
    public double scanDouble()throws IOException
    {
        double doub=0;
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        int neg=1;
        if(n=='-')
        {
            neg=-1;
            n=scan();
        }
        while(!isWhiteSpace(n)&&n!='.')
        {
            if(n>='0'&&n<='9')
            {
                doub*=10;
                doub+=n-'0';
                n=scan();
            }
            else throw new InputMismatchException();
        }
        if(n=='.')
        {
            n=scan();
            double temp=1;
            while(!isWhiteSpace(n))
            {
                if(n>='0'&&n<='9')
                {
                    temp/=10;
                    doub+=(n-'0')*temp;
                    n=scan();
                }
                else throw new InputMismatchException();
            }
        }
        return doub*neg;
    }
    public String scanString()throws IOException
    {
        StringBuilder sb=new StringBuilder();
        int n=scan();
        while(isWhiteSpace(n))
        n=scan();
        while(!isWhiteSpace(n))
        {
            sb.append((char)n);
            n=scan();
        }
        return sb.toString();
    }
    private boolean isWhiteSpace(int n)
    {
        if(n==' '||n=='\n'||n=='\r'||n=='\t'||n==-1)
        return true;
        return false;
    }
}