public static void main ( String [ ] args ) throws IOException {
  init ( System . in ) ;
  int [ ] abc = new int [ 3 ] ;
  for ( int i = 0 ;
  i < abc . length ;
  i ++ ) abc [ i ] = nextInt ( ) ;
  Arrays . sort ( abc ) ;
  int diff1 = abc [ 2 ] - abc [ 0 ] ;
  int diff2 = abc [ 2 ] - abc [ 1 ] ;
  if ( diff1 % 2 == 0 && diff2 % 2 == 0 ) System . out . println ( diff1 / 2 + diff2 / 2 ) ;
  else if ( diff1 % 2 == 1 && diff2 % 2 == 0 ) System . out . println ( 1 + diff2 / 2 + ( diff1 + 1 ) / 2 ) ;
  else if ( diff1 % 2 == 0 && diff2 % 2 == 1 ) System . out . println ( 1 + diff1 / 2 + ( diff2 + 1 ) / 2 ) ;
  else System . out . println ( 1 + ( diff1 - 1 ) / 2 + ( diff2 - 1 ) / 2 ) ;
}

public static void main ( String [ ] args ) throws IOException { init ( System . in ) ; int [ ] abc = new int [ 3 ] ; for ( int i = 0 ; i < abc . length ; i ++ ) abc [ i ] = nextInt ( ) ; Arrays . sort ( abc ) ; int diff1 = abc [ 2 ] - abc [ 0 ] ; int diff2 = abc [ 2 ] - abc [ 1 ] ; if ( diff1 % 2 == 0 && diff2 % 2 == 0 ) System . out . println ( diff1 / 2 + diff2 / 2 ) ; else if ( diff1 % 2 == 1 && diff2 % 2 == 0 ) System . out . println ( 1 + diff2 / 2 + ( diff1 + 1 ) / 2 ) ; else if ( diff1 % 2 == 0 && diff2 % 2 == 1 ) System . out . println ( 1 + diff1 / 2 + ( diff2 + 1 ) / 2 ) ; else System . out . println ( 1 + ( diff1 - 1 ) / 2 + ( diff2 - 1 ) / 2 ) ; }
(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 (expression_statement (method_invocation name: (identifier) arguments: (argument_list (field_access object: (identifier) field: (identifier))))) (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 (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: (field_access object: (identifier) field: (identifier))) update: (update_expression (identifier)) body: (expression_statement (assignment_expression left: (array_access array: (identifier) index: (identifier)) right: (method_invocation name: (identifier) arguments: (argument_list))))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (array_access array: (identifier) index: (decimal_integer_literal)) right: (array_access array: (identifier) index: (decimal_integer_literal))))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (binary_expression left: (array_access array: (identifier) index: (decimal_integer_literal)) right: (array_access array: (identifier) index: (decimal_integer_literal))))) (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (binary_expression left: (identifier) right: (decimal_integer_literal)))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (decimal_integer_literal) right: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (decimal_integer_literal)))))) alternative: (if_statement condition: (parenthesized_expression (binary_expression left: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)) right: (binary_expression left: (binary_expression left: (identifier) right: (decimal_integer_literal)) right: (decimal_integer_literal)))) consequence: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (decimal_integer_literal) right: (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (decimal_integer_literal)))))) alternative: (expression_statement (method_invocation object: (field_access object: (identifier) field: (identifier)) name: (identifier) arguments: (argument_list (binary_expression left: (binary_expression left: (decimal_integer_literal) right: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (decimal_integer_literal))) right: (binary_expression left: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) right: (decimal_integer_literal)))))))))))