import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    int n = Integer.parseInt(in.readLine());
    int[] a = new int[n];
    for(int i=0; i<n; i++) {
      a[i] = Integer.parseInt(in.readLine());
    }
    
    int count = 0;
    int currentButton = a[0];
    int[] ary = new int[n];
    boolean hantei = false;
    for(int i=0; i<n; currentButton=a[currentButton-1]) {
      if(currentButton==2) {
        count++;
        System.out.println(count);
        return;
      } else if(ary[currentButton-1]==2){
        System.out.println(-1);
        return;
      } else {
        count++;
        ary[currentButton-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