public static void main ( String [ ] args ) throws IOException {
  Scanner input = new Scanner ( System . in ) ;
  long n = input . nextLong ( ) - 1 ;
  long i = 1 ;
  while ( n - i >= 0 ) {
    n -= i ;
    i ++ ;
  }
  System . out . println ( n + 1 ) ;
}

public static void main ( String [ ] args ) throws IOException { Scanner input = new Scanner ( System . in ) ; long n = input . nextLong ( ) - 1 ; long i = 1 ; while ( n - i >= 0 ) { n -= i ; i ++ ; } System . out . println ( n + 1 ) ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (array_type element: (type_identifier) dimensions: (dimensions)) name: (identifier))) (throws (type_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: (binary_expression left: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) right: (decimal_integer_literal)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (while_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (identifier) right: (identifier)) right: (decimal_integer_literal))) body: (block (expression_statement (assignment_expression left: (identifier) right: (identifier))) (expression_statement (update_expression (identifier))))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal)))))))