import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		// 1行目個数、2行目の複数の数字を配列に格納
		//   3
		//   1 2 3
		int N = Integer.parseInt(br.readLine());
		int[] ii0 = new int[N+1];
		ii0[0]=0;
		for(int i = 1; i < N+1; i++){
			ii0[i] = Integer.parseInt(br.readLine());
		}
		

		int i=1;
		int count=0;
		while(i != 2){
			i = ii0[i];
			count += 1;
			if(count > N+1) { System.out.println(-1); return; }
		}
		


		System.out.println(count); return;
	}
	//-----------------------------------------------------------------
	// Debug.Print
	static void dp(String s) {
		System.out.println(s);
	}
	static void dp(StringBuilder s) { dp(s.toString()); }
	static void dp(int i) { dp(String.valueOf(i)); }
	static void dp(long i) { dp(String.valueOf(i)); }


	//-----------------------------------------------------------------
	// 入力値確認：リスト
	static void checkInput(List l) { System.out.println(l); }
	//-----------------------------------------------------------------
	// 入力値確認：配列、1次元、float型
	//   ＜使い方＞
	//     float[] f = new float[N];
	//     checkInput(f);
	static void checkInput(float[] i1) {
		StringBuilder sb = new StringBuilder();
		for(float i: i1) sb.append("[" + i + "]");
		System.out.println(sb);
	}
	//-----------------------------------------------------------------
	// 入力値確認：配列、1次元、int型
	//   ＜使い方＞
	//     int[] c = new int[N];
	//     checkInput(c);
	static void checkInput(int[] i1) {
		StringBuilder sb = new StringBuilder();
		for(int i: i1) sb.append("[" + i + "]");
		System.out.println(sb);
	}
	//-----------------------------------------------------------------
	// 入力値確認：配列、二次元、int型
	static void checkInput(int[][] i2) {
		StringBuilder sb = new StringBuilder();
		for(int[] i1: i2){
			for(int i: i1) sb.append("[" + i + "]");
			sb.append(System.getProperty("line.separator"));
		}
		System.out.println(sb);
	}
	//-----------------------------------------------------------------
	// 入力値確認：配列、二次元、int型
	static void checkInput(long[][] i2) {
		StringBuilder sb = new StringBuilder();
		for(long[] i1: i2){
			for(long i: i1) sb.append("[" + i + "]");
			sb.append(System.getProperty("line.separator"));
		}
		System.out.println(sb);
	}

}

/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