public static void main ( String [ ] args ) throws IOException {
  BufferedReader sc = new BufferedReader ( new InputStreamReader ( System . in ) ) ;
  int n = Integer . parseInt ( sc . readLine ( ) ) ;
  List < Integer > [ ] graph = new ArrayList [ n + 1 ] ;
  for ( int i = 0 ;
  i < n + 1 ;
  i ++ ) {
    graph [ i ] = new ArrayList < > ( ) ;
  }
  for ( int i = 0 ;
  i < n - 1 ;
  i ++ ) {
    String [ ] s = sc . readLine ( ) . split ( "\\s" ) ;
    int a = Integer . parseInt ( s [ 0 ] ) ;
    int b = Integer . parseInt ( s [ 1 ] ) ;
    graph [ a ] . add ( b ) ;
    graph [ b ] . add ( a ) ;
  }
  BigInteger [ ] colorCount = new BigInteger [ 2 ] ;
  colorCount [ RED ] = BigInteger . ZERO ;
  colorCount [ BLUE ] = BigInteger . ZERO ;
  colorGraph ( graph , new boolean [ n + 1 ] , 1 , RED , colorCount ) ;
  System . out . println ( colorCount [ BLUE ] . multiply ( colorCount [ RED ] ) . subtract ( ( BigInteger . valueOf ( n - 1 ) ) ) ) ;
}

public static void main ( String [ ] args ) throws IOException { BufferedReader sc = new BufferedReader ( new InputStreamReader ( System . in ) ) ; int n = Integer . parseInt ( sc . readLine ( ) ) ; List < Integer > [ ] graph = new ArrayList [ n + 1 ] ; for ( int i = 0 ; i < n + 1 ; i ++ ) { graph [ i ] = new ArrayList < > ( ) ; } for ( int i = 0 ; i < n - 1 ; i ++ ) { String [ ] s = sc . readLine ( ) . split ( " \\ s " ) ; int a = Integer . parseInt ( s [ 0 ] ) ; int b = Integer . parseInt ( s [ 1 ] ) ; graph [ a ] . add ( b ) ; graph [ b ] . add ( a ) ; } BigInteger [ ] colorCount = new BigInteger [ 2 ] ; colorCount [ RED ] = BigInteger . ZERO ; colorCount [ BLUE ] = BigInteger . ZERO ; colorGraph ( graph , new boolean [ n + 1 ] , 1 , RED , colorCount ) ; System . out . println ( colorCount [ BLUE ] . multiply ( colorCount [ RED ] ) . subtract ( ( BigInteger . valueOf ( 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 (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 (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))))) (local_variable_declaration type: (array_type element: (generic_type (type_identifier) (type_arguments (type_identifier))) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (type_identifier) dimensions: (dimensions_expr (binary_expression left: (identifier) 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: (binary_expression left: (identifier) right: (decimal_integer_literal))) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (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: (binary_expression left: (identifier) right: (decimal_integer_literal))) update: (update_expression (identifier)) body: (block (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)) name: (identifier) arguments: (argument_list (string_literal))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (decimal_integer_literal)))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (decimal_integer_literal)))))) (expression_statement (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (identifier)))) (expression_statement (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (identifier)))))) (local_variable_declaration type: (array_type element: (type_identifier) dimensions: (dimensions)) declarator: (variable_declarator name: (identifier) value: (array_creation_expression type: (type_identifier) dimensions: (dimensions_expr (decimal_integer_literal))))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (field_access object: (identifier) field: (identifier)))) (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (field_access object: (identifier) field: (identifier)))) (expression_statement (method_invocation name: (identifier) arguments: (argument_list (identifier) (array_creation_expression type: (boolean_type) dimensions: (dimensions_expr (binary_expression left: (identifier) right: (decimal_integer_literal)))) (decimal_integer_literal) (identifier) (identifier)))) (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (method_invocation object: (method_invocation object: (array_access array: (identifier) index: (identifier)) name: (identifier) arguments: (argument_list (array_access array: (identifier) index: (identifier)))) name: (identifier) arguments: (argument_list (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (binary_expression left: (identifier) right: (decimal_integer_literal))))))))))))