import java.util.Scanner;

class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		int[] a = new int[n];
    for(int i=0; i<n; i++){
      a[i] = sc.nextInt();
    }

    int j = 0;
    int cnt = 0;
    int pre;
    while(true){
      if(a[j] != -1 && a[j] - 1 != j){
        pre = j;
        j = a[j] - 1;
        a[pre] = -1;
        cnt++;
        if(j==1){
          System.out.print(cnt);
          return;
        }
      }else{
        System.out.print("-1");
        return;
      }
    }

	}

}

/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