public static void main ( String [ ] args ) {
  Scanner scan = new Scanner ( System . in ) ;
  int x = scan . nextInt ( ) ;
  int y = scan . nextInt ( ) ;
  scan . close ( ) ;
  if ( Math . abs ( x - y ) > 1 ) {
    System . out . println ( '0' ) ;
    return ;
  }
  frac [ 0 ] = 1 ;
  for ( int i = 1 ;
  i <= 100000 ;
  i ++ ) frac [ i ] = frac [ i - 1 ] * i % ZYY ;
  long ans = frac [ x ] * frac [ y ] % ZYY ;
  if ( x == y ) ans = ans * 2 % ZYY ;
  System . out . println ( ans ) ;
  return ;
}

public static void main ( String [ ] args ) { Scanner scan = new Scanner ( System . in ) ; int x = scan . nextInt ( ) ; int y = scan . nextInt ( ) ; scan . close ( ) ; if ( Math . abs ( x - y ) > 1 ) { System . out . println ( '0' ) ; return ; } frac [ 0 ] = 1 ; for ( int i = 1 ; i <= 100000 ; i ++ ) frac [ i ] = frac [ i - 1 ] * i % ZYY ; long ans = frac [ x ] * frac [ y ] % ZYY ; if ( x == y ) ans = ans * 2 % ZYY ; System . out . println ( ans ) ; return ; }
(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)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (if_statement condition: (parenthesized_expression (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (identifier)))) right: (decimal_integer_literal))) consequence: (block (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (character_literal)))) (return_statement))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (decimal_integer_literal)) 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: (decimal_integer_literal)) update: (update_expression (identifier)) body: (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (identifier)) right: (identifier))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (array_access array: (identifier) index: (identifier))) right: (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (identifier))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) (return_statement)))