public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int s = sc . nextInt ( ) ;
  int t = sc . nextInt ( ) ;
  int [ ] p = new int [ n + 1 ] ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    p [ i ] = sc . nextInt ( ) ;
  }
  if ( s == t ) {
    System . out . println ( "0" ) ;
    return ;
  }
  int count = 0 , strt = s ;
  while ( s != t ) {
    s = p [ s ] ;
    count ++ ;
    if ( s == strt ) {
      System . out . println ( "-1" ) ;
      return ;
    }
    else if ( s == t ) {
      System . out . println ( count ) ;
    }
  }
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int s = sc . nextInt ( ) ; int t = sc . nextInt ( ) ; int [ ] p = new int [ n + 1 ] ; for ( int i = 1 ; i <= n ; i ++ ) { p [ i ] = sc . nextInt ( ) ; } if ( s == t ) { System . out . println ( "0" ) ; return ; } int count = 0 , strt = s ; while ( s != t ) { s = p [ s ] ; count ++ ; if ( s == strt ) { System . out . println ( " - 1" ) ; return ; } else if ( s == t ) { 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: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (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: (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)))))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (return_statement))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal)) declarator: (variable_declarator name: (identifier) value: (identifier))) (while_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) body: (block (expression_statement (assignment_expression left: (identifier) right: (array_access array: (identifier) index: (identifier)))) (expression_statement (update_expression (identifier))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) (return_statement)) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))))))))))