import std.algorithm, std.container, std.conv, std.math, std.range, std.typecons, std.stdio, std.string;

auto rdsp(){return readln.splitter;}
void pick(R,T)(ref R r,ref T t){t=r.front.to!T;r.popFront;}
void readV(T...)(ref T t){auto r=rdsp;foreach(ref v;t)pick(r,v);}
void readC(T...)(size_t n,ref T t){foreach(ref v;t)v=new typeof(v)(n);foreach(i;0..n){auto r=rdsp;foreach(ref v;t)pick(r,v[i]);}}

void main()
{
  int n; readV(n);
  int[] a; readC(n, a); a[] -= 1;

  auto v = new bool[](n), c = 0, b = 0;
  v[0] = true;

  for (;;) {
    b = a[b];

    if (v[b]) {
      writeln(-1);
      return;
    }

    ++c;
    if (b == 1) {
      writeln(c);
      return;
    }

    v[b] = true;
  }
}
