public static void main ( String [ ] srgs ) {
  Scanner scan = new Scanner ( System . in ) ;
  int a = scan . nextInt ( ) ;
  int b = scan . nextInt ( ) ;
  int sa = b - a ;
  int s = 0 ;
  for ( int i = 0 ;
  i <= 999 ;
  i ++ ) {
    s += i ;
    if ( i == sa ) {
      System . out . println ( s - b ) ;
      return ;
    }
  }
  scan . close ( ) ;
}

public static void main ( String [ ] srgs ) { Scanner scan = new Scanner ( System . in ) ; int a = scan . nextInt ( ) ; int b = scan . nextInt ( ) ; int sa = b - a ; int s = 0 ; for ( int i = 0 ; i <= 999 ; i ++ ) { s += i ; if ( i == sa ) { System . out . println ( s - b ) ; return ; } } scan . close ( ) ; }
(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: (binary_expression left: (identifier) right: (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (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: (block (expression_statement (assignment_expression left: (identifier) right: (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 (binary_expression left: (identifier) right: (identifier))))) (return_statement))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))