public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int N = sc . nextInt ( ) ;
  boolean [ ] n = new boolean [ N + 1 ] ;
  boolean isEnd = false ;
  for ( int i = 1 ;
  i <= N ;
  i ++ ) {
    n [ i ] = false ;
  }
  int [ ] a = new int [ N + 1 ] ;
  for ( int i = 1 ;
  i <= N ;
  i ++ ) {
    a [ i ] = sc . nextInt ( ) ;
  }
  sc . close ( ) ;
  int count = 0 ;
  int i = 1 ;
  while ( true ) {
    if ( n [ i ] == false ) {
      n [ i ] = true ;
      count ++ ;
      if ( a [ i ] == 2 ) {
        break ;
      }
      i = a [ i ] ;
    }
    else {
      count = - 1 ;
      break ;
    }
  }
  System . out . println ( count ) ;
  ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int N = sc . nextInt ( ) ; boolean [ ] n = new boolean [ N + 1 ] ; boolean isEnd = false ; for ( int i = 1 ; i <= N ; i ++ ) { n [ i ] = false ; } int [ ] a = new int [ N + 1 ] ; for ( int i = 1 ; i <= N ; i ++ ) { a [ i ] = sc . nextInt ( ) ; } sc . close ( ) ; int count = 0 ; int i = 1 ; while ( true ) { if ( n [ i ] == false ) { n [ i ] = true ; count ++ ; if ( a [ i ] == 2 ) { break ; } i = a [ i ] ; } else { count = - 1 ; break ; } } System . out . println ( count ) ; ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) body: (block (local_variable_declaration type: (type_identifier) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (type_identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (local_variable_declaration type: (array_type element: (boolean_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (boolean_type) dimensions: (dimensions_expr (binary_expression left: (identifier) right: (decimal_integer_literal)))))) (local_variable_declaration type: (boolean_type) declarator: (variable_declarator name: (identifier) value: (false))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (false))))) (local_variable_declaration type: (array_type element: (integral_type) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (integral_type) dimensions: (dimensions_expr (binary_expression left: (identifier) right: (decimal_integer_literal)))))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (while_statement condition: (parenthesized_expression (true)) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (false))) consequence: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (true))) (expression_statement (update_expression (identifier))) (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal))) consequence: (block (break_statement))) (expression_statement (assignment_expression left: (identifier) right: (array_access array: (identifier) index: (identifier))))) alternative: (block (expression_statement (assignment_expression left: (identifier) right: (unary_expression operand: (decimal_integer_literal)))) (break_statement))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier))))))