public static void main ( String [ ] args ) {
  Scanner sc = new Scanner ( System . in ) ;
  int n = sc . nextInt ( ) ;
  int m = sc . nextInt ( ) ;
  ArrayList < ArrayList < Integer >> graph = new ArrayList < > ( ) ;
  for ( int i = 1 ;
  i <= n ;
  i ++ ) {
    graph . add ( new ArrayList < Integer > ( ) ) ;
  }
  for ( int i = 0 ;
  i < m ;
  i ++ ) {
    int start = sc . nextInt ( ) ;
    int end = sc . nextInt ( ) ;
    graph . get ( start - 1 ) . add ( end - 1 ) ;
    graph . get ( end - 1 ) . add ( start - 1 ) ;
  }
  int [ ] sizeCount = new int [ n ] ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    int count = graph . get ( i ) . size ( ) ;
    sizeCount [ count ] = sizeCount [ count ] + 1 ;
  }
  if ( sizeCount [ 2 ] == n - 2 && sizeCount [ 1 ] == 2 ) System . out . println ( "bus topology" ) ;
  else if ( sizeCount [ 2 ] == n ) System . out . println ( "ring topology" ) ;
  else if ( sizeCount [ n - 1 ] == 1 && sizeCount [ 1 ] == n - 1 ) System . out . println ( "star topology" ) ;
  else System . out . println ( "unknown topology" ) ;
}

public static void main ( String [ ] args ) { Scanner sc = new Scanner ( System . in ) ; int n = sc . nextInt ( ) ; int m = sc . nextInt ( ) ; ArrayList < ArrayList < Integer > > graph = new ArrayList < > ( ) ; for ( int i = 1 ; i <= n ; i ++ ) { graph . add ( new ArrayList < Integer > ( ) ) ; } for ( int i = 0 ; i < m ; i ++ ) { int start = sc . nextInt ( ) ; int end = sc . nextInt ( ) ; graph . get ( start - 1 ) . add ( end - 1 ) ; graph . get ( end - 1 ) . add ( start - 1 ) ; } int [ ] sizeCount = new int [ n ] ; for ( int i = 0 ; i < n ; i ++ ) { int count = graph . get ( i ) . size ( ) ; sizeCount [ count ] = sizeCount [ count ] + 1 ; } if ( sizeCount [ 2 ] == n - 2 && sizeCount [ 1 ] == 2 ) System . out . println ( " bus ▁ topology " ) ; else if ( sizeCount [ 2 ] == n ) System . out . println ( " ring ▁ topology " ) ; else if ( sizeCount [ n - 1 ] == 1 && sizeCount [ 1 ] == n - 1 ) System . out . println ( " star ▁ topology " ) ; else System . out . println ( " unknown ▁ topology " ) ; }
(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: (generic_type (type_identifier) (type_arguments (generic_type (type_identifier) (type_arguments (type_identifier))))) declarator: (variable_declarator name: (identifier) value: (object_creation_expression type: (generic_type (type_identifier) (type_arguments)) arguments: (argument_list)))) (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 (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (object_creation_expression type: (generic_type (type_identifier) (type_arguments (type_identifier))) arguments: (argument_list))))))) (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 (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: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal)))) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal))))) (expression_statement (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal)))) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal))))))) (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 (identifier))))) (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 (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))) name: (identifier) arguments: (argument_list)))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (binary_expression left: (array_access array: (identifier) index: (identifier)) right: (decimal_integer_literal)))))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (decimal_integer_literal)) right: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (binary_expression left: (array_access array: (identifier) index: (decimal_integer_literal)) right: (decimal_integer_literal)))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (array_access array: (identifier) index: (decimal_integer_literal)) right: (identifier))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (array_access array: (identifier) index: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (decimal_integer_literal)) right: (binary_expression left: (array_access array: (identifier) index: (decimal_integer_literal)) right: (binary_expression left: (identifier) right: (decimal_integer_literal))))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))) alternative: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (string_literal)))))))))