public static void main ( String args [ ] ) {
  Scanner sc = new Scanner ( System . in ) ;
  int A = sc . nextInt ( ) ;
  int B = sc . nextInt ( ) ;
  int C = sc . nextInt ( ) ;
  long K = sc . nextLong ( ) ;
  if ( K % 2 == 0 ) {
    System . out . println ( A - B ) ;
  }
  else {
    System . out . println ( B - A ) ;
  }
}

public static void main ( String args [ ] ) { Scanner sc = new Scanner ( System . in ) ; int A = sc . nextInt ( ) ; int B = sc . nextInt ( ) ; int C = sc . nextInt ( ) ; long K = sc . nextLong ( ) ; if ( K % 2 == 0 ) { System . out . println ( A - B ) ; } else { System . out . println ( B - A ) ; } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (type_identifier) name: (identifier) dimensions: (dimensions))) 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: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)))))) alternative: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)))))))))